The worrying thing about the lake is, it wants him to walk into it.
That's the only reason Derek stops, stuttering to a halt even as his weight and momentum make him sway forward. His boots are braced against a few sturdy stones, on the cusp of that last step forward, but he pulls himself back before he can actually splash right in, clothes and all, the way Stiles did. He should be worried, panicked even, but instead he just feels calm, tranquil in a way he hasn't been in... ever, maybe. That's how he knows for sure that it's doing something to him; the sudden peace of mind can't possibly be his own.
He can tell that the water is frigid; the wind that whips across its surface is winter-cold, glacier-cold, and there's actual frost glistening on the rocks beneath his boots. The lake's surface is glossy black, its depths opaque, and the water shouldn't be that freakishly, preternaturally flat; under the force of the wind it should at least be rippled. Even if the winds were calm, it's only been moments since Stiles disappeared entirely beneath the surface, and surely there should be some sign of his presence, a rising of bubbles to mark his place beneath the water.
There isn't, though. There wasn't when he walked in, either, not that Derek had been able to see, but he'd been far enough off that he'd only managed a baffled, "Stiles, what are you—" before Stiles had taken one step into the lake, and then another, and then another, until the water had quietly swallowed him whole.
Stiles has been under too long by far, should've broken the surface by now if he were able, but Derek isn't sure what to do, how to help, when he can feel how hungry the lake is. He knows if he walks in, he'll never walk out again. He wants to do it anyway.
He doesn't realize he's taken off his shirt until it's already done; he looks down at his hands and the cotton is clutched between clawed fingers. His feet are bare, too, his cold toes brushing frost from the stones beneath his feet. He doesn't remember taking his boots off, or his socks, and they're nowhere around. He frowns, drops the t-shirt into the water, and watches it disappear, quickly and comprehensively; it's hardly darkened with water before it's sucked down into a blackness that's too deep to be natural, as if the familiar pebbled lakebed, the one he remembers beneath his feet from the countless summer swims of his childhood, has given way to a new, mind-boggling depth. He breathes in, air so cold it makes his lungs burn, and his hands work mechanically at his belt buckle, his zipper, and it's only a moment's work to slip out of his jeans and underwear, even if he isn't entirely sure why he's doing it. The lake takes those, too, though Derek only realizes he's given them up as they too disappear without so much as a ripple to mark their passing.
He's naked now, and cold, and he doesn't know why he's taken off his clothes, except he does. Because people take off their clothes before they get into the water, don't they? And it's cold out here, but the water will be so warm, it's obviously a hot spring, it—
He stops himself, wobbling awkwardly on one leg, his toes just above the water, his body eager for the heat and the quiet and the unstoppable calm. He doesn't want it, because he's not calm. Stiles is in the water, doesn't possibly have the lung capacity to still even be alive in there, and Derek's not calm about that. He's angry, he's furious, at this trespass on his territory, this interloper in his own hunting ground and his own mind, this thief that's robbed him of his mate, that's possibly robbed Stiles of his life.
Derek shifts into his Alpha form without even thinking about it, lets the change sweep over him like fire, and when his bones reshape themselves and the fur bristles from his skin, the lake's hold on him snaps too, like a buoy suddenly untethered. He roars his anger across the water, so loud that the water finally moves, vibrates with the force of it. He howls, and though it's not a language Stiles will ever understand, he's still calling his human home, back to his pack, back to Derek. The water shivers. The wind subsides.
His howl's still echoing back on itself when Stiles suddenly breaks the surface of the water, a good hundred feet out, his arms flailing frantically, his gaping mouth heaving in breaths so desperate they'd be audible even to human ears. He splashes, trying to wipe the water from his eyes, trying to get his bearings, but the sound of Derek's voice is enough to draw him toward the shore, a churning inelegant mess in the water, clothes dragging at him. When the water turns shallow he crawls on his knees, then staggers to his feet, shuddering and shivering, and all Derek can do is pace the shoreline, snarling, waiting for him to get there, trying to dream up a hundred ways to kill a lake. He feels impotent and useless, rage twisting his muscles tight, but helplessly afraid to splash into the water and drag Stiles in.
"Little h-help?" Stiles bites out, between convulsively clattering teeth. He's already stumbling into Derek's arms, and Stiles comes so easily that Derek almost doesn't realize that he's still in his other shape until he sees the dark fur and his clawed hand against the almost blue cast of Stiles' skin.
He pulls Stiles against him without even thinking about it, ignoring the cold and wet, wrapping his arms around Stiles' back and trying to hunch the rest of himself over Stiles' body.
"Oh my god," Stiles gasps against him, the words muffled against the thick fur at Derek's chest. It almost sounds erotic, for a moment, the blissful moan of a lover, but then Stiles squirms in Derek's hold and it's plain that he's just trying to get closer to warm himself up, would probably crawl right inside Derek's ribcage, if he could.
Derek says, "You—" but then he huffs and gives up, words too difficult to form with his long tongue, broad muzzle, not-quite-human throat. He runs a broad, clawed hand down Stiles' body instead, cradles the back of his skull, palms the nape of his neck, presses down the line of his spine, answering the question for himself.
"I'm good," Stiles says, obviously picking up on Derek's unarticulated question. It's obviously a lie, because the words come out whisper-quiet and wobbling. "I'm okay, for somebody who just got vomited up by a mind-controlling lake. I'm just really cold. And you're a fucking furnace."
The noise Derek makes is a little embarrassing, so he buries his nose against the cold, clammy skin of Stiles' neck, huffs out a hot breath like he can warm Stiles that way, one square inch of skin at a time.
"I think you scared the whatever-it-was away," Stiles says, and stretches out a foot to prod the water with it, like he's kicking a corpse to make sure it's dead.
Derek picks Stiles up completely to snatch him back, but he isn't fast enough, and nothing happens anyway; the water, clear now and completely ordinary-looking, ripples predictably around the splash of Stiles' sneaker against its surface. Stiles doesn't seem eager to walk back in to his doom, either.
"See?" Stiles says. "We can research it later, since I don't think your plan of clawing it to death is going to work anyway. You can't maim water, Derek."
Derek figures he can maim anything, if he tries hard enough, but he's learned over the years that there's something to be said for retreat in the face of completely baffling adversaries. Regardless, his biggest problem at the moment is Stiles, who is cold and wet and unhappy. He can figure out how to murder a lake another day.
Stiles seems to agree, because he says, "Hey, let's go back to the house. Can I ride on your back like a baby lemur?"
Derek's answer is a wordless grumble, but he also drops down to all fours and crouches low, giving Stiles all the opening he needs to clamber up onto Derek's furred back. It's not comfortable; Stiles is soaked, his knees are digging painfully into Derek's flanks, his hands are tugging at the fur on Derek's shoulders. When Derek actually gets up and starts moving, Stiles just clings harder and seems somehow, impossibly, to become even bonier than he already was.
The route home is a bit longer than it would be if Derek were alone; he has to stick to more well-established trails to keep the underbrush and low-lying tree branches from sweeping his passenger off. But Stiles at least has relaxed and found his balance in the rhythm of Derek's gait by the journey's mid-point, even if his shivering has intensified. It's almost nice, loping through the familiar Preserve with Stiles' weight pressed against him. Derek's a little self-conscious about his Alpha form, usually, and he tends not to hold it when Stiles is around because it's more difficult to meet Stiles' sass with sarcasm when his mouth isn't really equipped to form words. But he thinks it might be nice, sometime, to try this again in an non-emergency situation. He could take Stiles out to that quiet spot he likes, with all the wildflowers and that soft, deep-grassed, sun-drenched hollow where he likes to nap sometimes as a wolf. He could topple Stiles off his back right there, could press him down into the grass and—
No. Nope. He's not going there. Right now.
He's got more important things to think about at the moment, because he's trotting up the steps onto the front porch of their house, and Stiles is sliding clumsily off his back. It's not just Stiles' usual level of clumsy — that mostly went away when he grew into his shoulders and took up parkour — it's a white-faced, groggy-looking clumsy. He's stopped shivering, and Derek's sure that's not good.
He shifts back to his human shape, just in time to catch Stiles as he starts to topple. "Get inside, idiot," he says, fond, exasperated, and worried all at once. "Let's get these wet clothes off."
Stiles is already trying to get out of his jacket, but it's not really working; his coordination is shot, and Derek has to help him. The garment drops with a splat in the tiled entryway, as Derek hauls them both through the front door and keeps peeling Stiles out of sodden layers.
"I'm good," Stiles finally says, when Derek is trying to get him out of his clinging jeans. He's not actually good; he slurs the words and his hands are weak and fumbling. He doesn't do a very good job of pushing Derek off of him, either, and he stops trying when he's naked and Derek's hauling him up the stairs, lifting him more than letting him walk.
"What should I do? Stiles? I don't remember the shit for hypothermia. Who even gets that in coastal California? What am I supposed to do, warm bath?"
"That sounds awful," Stiles says, frowning. "Doesn't that... heart attack, or something?"
He leaves out part of his train of thought completely, but Derek doesn't like the sound of the part Stiles does remember.
"Okay, so what, then? Should I call Melissa? Oh, fuck. My phone's in the lake. Along with my pants."
Stiles laughs against his throat, and even his breath feels cool. "What about just... you change back, and we get in bed. Like a bearskin rug."
It takes a second before Derek even gets what he means, and then another second for Derek to stop being offended at being compared to a bearskin rug. He'll make Stiles pay for it later, though, because they're in the bedroom now, they've officially reached the bed, and his priority now is getting Stiles beneath the blankets. They're not much — Beacon Hills isn't exactly freezing, usually — but they'll help trap body heat, at least.
Derek manhandles Stiles into the bed and beneath the sheets, leaves them half pulled back for himself, and then pushes the change again, sprouts fur, grows bigger. His body temperature is naturally a bit higher this way, which should help, and his pelt should help warm Stiles a little, too, if he makes a blanket of himself. Or a rug. Little shit.
He climbs into the bed carefully, ignores Stiles' childish ooooh sound and the way Stiles clutches at him like he's a teddy bear and a heating pad all in one. He does flip Stiles around, though, so Stiles is the little spoon, his back to Derek's chest, and he curls Stiles up so that he can trap those ice-cold feet between his own thighs. He presses Stiles' body against the bed and tries to cover it with his own, as much as he's able, until Stiles grunts like he can't breathe anymore.
It doesn't take long for Stiles to start shivering again, which Derek is pretty sure is a good sign. It takes maybe a half an hour before he actually starts talking, but when he does the slur is gone from his voice, and he's complaining, which for Stiles is generally a sign of health.
"My nose is really cold, Derek," is the first thing he says, in a really piteous tone of voice.
Derek's been breathing on Stiles' face, trying to warm it that way, but he's not proud: he puts his mouth to work in another way, licking broad stripes over the planes of Stiles' nose, cheekbones, forehead, jaw. It should actually stimulate blood flow and warm him up a little, but also has the satisfying effect of making Stiles squirm and curse Derek's name.
When he finally relents, stops licking, and settles again, there's only silence for maybe a minute before Stiles offers another complaint.
"My fingers are cold, too," he says. The tone of his voice is the one that he thinks is sly. It's actually just obvious, but Derek suspects it's meant to be.
Derek can only reach one hand — the other is wedged beneath Stiles' armpit; this one is curled around Stiles' own arm on the near side — but he makes the most of it, laving the fingers with his tongue, lovingly slobbering on the knuckles, mouthing at the bony wrist. When Stiles picks the hand up, like he wants Derek to give his palm the same treatment, Derek instead opens his whole mouth, draws Stiles' hand delicately in with his tongue, closes his canines carefully around Stiles' wrist, enveloping the entire appendage in moist heat.
Stiles is frozen, but he's also twisted around enough that he can see what Derek's doing, and he doesn't look like he can quite believe it.
"Holy shit," he breathes, and his pupils are a wide, inky black, though whether it's with shock or arousal, it's impossible to tell. "You can fit my entire fucking hand in your mouth. That is... that is frighteningly attractive."
Oh. Arousal, then.
Derek grunts around Stiles' hand, but doesn't let it go, presses his tongue up against Stiles' palm and breathes through his nose; he's certain it's only his imagination, but he thinks he can taste the pulse in Stiles' wrist. When Stiles' fingers seem warm enough, he opens his mouth and lets Stiles gingerly take the hand back, licks the taste of that skin from his own mouth, just to savor it.
Stiles is still staring at him, like he's never seen Derek before. It's probably fair; Derek doesn't shift to the Alpha form much — it's too much trouble, usually, and he's kind of tired of losing clothes — but when he has in the past it's usually been in the midst of a fight, or in the dark. Certainly never in their bedroom, in the early hours on a weekday, out of place among the bedsheets like a wild animal invited indoors.
"Hey, Derek," Stiles says.
Derek growls, low in his throat, and rolls to press Stiles more firmly against the bed in an attempt to make him go to sleep. He's warming up, but he still needs to rest. Whatever it is that Stiles wants this time, they can talk about it in the morning.
"Dereeeeeek, come on." Stiles wriggles beneath him, but Derek doesn't give ground, and finally Stiles relents with a grumbled, "Fine," and goes limp, like he's planning to feign sleep until Derek lets his guard down.
A few minutes later, the ploy becomes reality; Stiles sinks suddenly and profoundly into real sleep, his mouth open against the sheets, his heartbeat going slow and steady. Derek just lies there and listens to it for the longest time, reassuring himself that it's real, that it's still there, that this isn't some dream, that Stiles hasn't been lost in the depths of a more profound darkness, cold and alone.
Derek curls around that softly breathing body a little tighter. Stiles' feet have slipped from between Derek's thighs, and they feel warm enough now, but Derek flicks his tail over them, anyway, before he chases Stiles into sleep.
He wakes to the very pleasant sensation of fingers buried in the fur over his stomach. He cracks his eyes open reluctantly, waiting for the inevitable crack about dogs and belly rubs, but it never comes; Stiles is just lying there, watching his own fingers kneading at Derek's body like a cat with a blanket, seemingly mesmerized by the fur beneath his hands.
Derek grunts to let Stiles know he's awake, and stretches a little, careful not to move enough to dislodge Stiles. He gives Stiles a cursory looking-over, making sure he's alright, but Stiles is beyond warm now, blankets thrown back from his body, delicious sweat-smell beneath his armpits, at his crotch, down the line of his back where they'd been pressed together in sleep. Stiles smells like Derek all over, shed hairs clinging to him, the scent amplified by the heat between them.
"I've never seen you like this," Stiles says. "Not in the daylight, anyway." There's plenty of that, now, streaming in through the windows, most of the drapes left open the night before.
Stiles grows a little bolder with his hands, sweeping them down Derek's body, fingers firm along each line and plane, like he's trying to map out exactly what Derek looks like, beneath the fur. He's looking, too, intent the same way he gets when he's studying, taking everything of Derek in, like he wants to see how the man fits beneath the surface of the wolf's skin.
It must be strange, Derek thinks, to wake up with a monster in bed, even if you knew you were lying down with one. His body in this shape is only vaguely human; his chest is narrower and deeper, to give his shoulders a greater range of movement, allow him to run comfortably and quickly on all fours. His whole frame is bigger, his legs — his hind legs — curved in a completely inhuman way, his knees and heels pulled higher, his gait pushed up onto the balls of his feet, his clawed feet with hardly an echo of his human shape left at all. His hands are broader, rougher, and more deadly; they're the most alien thing about him, he thinks, because they look so human, at first glance. He's accustomed to the animal that he is, doesn't think of wolf and man as two separate entities, but even he still isn't at home inside this body. He wasn't capable of shifting this way, before he became an Alpha, and after, it took a long time to master this particular skill. He doesn't use it much, hardly even knows what he looks like, what it must be like for Stiles to see him this way.
Stiles, though, doesn't seem to have a problem with it. He pulls himself up so he's crouched on his knees, and Derek thinks for a moment that he's going to leave, but he's only giving himself a better vantage point. He says, "Do you mind if I—" but he doesn't finish the thought, or wait for an answer. He just reaches out again, running his hands down the roped muscle of Derek's arm, traces the veins beneath the smooth fur at Derek's wrist, rubs a finger against the spongy paw pads on Derek's fingertips, the pattern of them on Derek's palm, the thick claws arcing from each fingertip.
Derek rolls onto his back, stretching out and relaxing, intent on just lying there comfortably until Stiles is finished with his explorations. He doesn't mind, really, almost wishes he could do the same, catalog himself from the outside in. He more or less knows what he looks like, but he's never exactly changed like this in front of a mirror.
"I don't get how you're so much bigger," Stiles says, almost to himself. "Like you've literally gained mass. Which shouldn't be possible except, you know. Magic."
Derek huffs, flexes his hand beneath Stiles' seeking fingers until they're knit together, palm to palm. It feels strange and perfect and right, all at the same time, the way touching Stiles always does, like it's a miracle and surprise every time it happens, even for as long as it's been happening. He looks different through Derek's wolf-eyes, but Derek at least is used to that, accustomed to the way the world goes sharper, a little flatter, more intricately detailed when his eyes change. The first time he shifted, as a boy, the flood of information had completely fucked with his depth perception; he'd had to spend a month learning how to see again just so he wouldn't fall on his face. Now it's easy and familiar, to be able to see the texture of Stiles' skin, the levels of depth in his eyes, the strands of his hair each individual and so detailed that looking was nearly the same as touching.
Derek gives in to temptation and runs his free hand carefully through Stiles' wild thatch of hair, scratching his claws delicately over the thin skin of Stiles' scalp. His own fingers aren't as sensitive anymore, thickly padded for quadrupedal walking, not very dexterous either. It still feels good, though, to have the shape of Stiles' skull cradled in his palm, to know that this is something delicate that he will never, ever break.
It's profoundly satisfying the way Stiles arches into it, humming under his breath, encouraging more. He plants a hand against Derek's stomach, like he needs it to hold his balance — maybe he does, since his eyes have fallen shut — but his fingers dig in again, too, finding the planes of muscle beneath the fur.
When he opens his eyes and looks down at Derek, there's a hunger there that Derek knows well, has never been able to say no to. He's the wolf, but Stiles has always been the one with unexpected appetites.
"Derek," Stiles says, and it's not a question or a statement or anything, really; Derek doesn't know what it means.
He tilts his head to one side, universal canine language for a question mark, but Stiles is already asking the question in another way, running light, delicate fingers over the thin fur and soft skin of the sheath covering Derek's cock.
Derek's breath rushes from his lungs, and he lets out a whimper without even thinking about it. It's not a no, or a yes; it's the wordless, helpless whine of an animal, and Derek can't understand why Stiles wants this, wants him like this.
"Hey, you wanna tap out?" Stiles says, and he leans over Derek's body like he wants to kiss, before he realizes that Derek's mouth isn't really capable of it. He does it anyway, though, presses his lips to the corner of Derek's mouth, rubs his cheek along Derek's muzzle, drops a chaste little kiss on the tip of Derek's black, canine nose.
Derek can't even think around it, Stiles' heady, complex scent, the rush of Stiles' breath against his own mouth and he can taste it. That hand is still stroking at his cock through the sheath, growing bolder, pressing harder. Stiles' other hand is wrapped around his own cock, lazily teasing himself into hardness. Derek whines again, unsure exactly what he's asking for, only wanting more and harder and everything.
Stiles grins against his mouth, sharper than any wolf, and then pulls back a little, returns his attention to what his hand is doing, examining Derek's rearranged dick like it's a puzzle he needs to unlock. He pulls the sheath back, like the foreskin it essentially is, and exposes the tip of the cock inside. His other hand reaches for Derek's balls, hanging low between furred thighs, and he seems satisfied with the way Derek jolts and groans when he cradles them in his palm.
"You ever done this? Played with yourself?"
Derek shakes his head. It seems stupid not to know his own body, but the idea of actually doing it himself is a little absurd, too. He's definitely never lounged around at home in his Alpha form, checking out how the plumbing works, trying to bring himself off with his thick, rough fingers. This body is for intimidating things, killing things, not for—
"It's different," Stiles says. "There's not much of a head on it. Fuck, I bet that's smooth going in."
Not for that. Except maybe it is.
Stiles looks excited about it, which is a whole new level of insane even for him, but it's hot, too, that he wants Derek this way. Every way. Derek feels himself twitch just at the thought of it, his cock beginning to push its own way out of the sheath, pink and slick. Stiles drops a hand to his own cock again, giving himself rough, fast pulls, like he can't bother to spare himself too much attention but he can't help it either, like just the sight of Derek's cock is turning him on, like he wants to compare the shape and weight of a human cock with the one in his other hand.
"Fuck," Stiles breathes, staring down at both of them like he can't quite believe it. He loops his fingers around the tip of Derek's cock, tight, like he's giving Derek a hole to fuck into.
The sensation of it is electric, has Derek growling and thrusting mindlessly up into Stiles' grip, his cock pressing itself up out of the sheath and into that grip. He looks down at himself, at Stiles' hand on him, and although everything about himself seems strange and foreign, everything about Stiles is the same: open panting mouth, clever hands, hard glimmering eyes, like orgasms are a competition he's intent on winning.
"Christ, that's unexpectedly big, I can't believe you were hiding all that in there," Stiles says. His hand starts working at Derek's cock, re-learning it. It doesn't really thicken or get harder the way a human's would, but it starts out plenty big enough, and it keeps pushing, up and out, until Stiles' hands are full with it, and the swelling at the base pushes out, too, and fucking Christ, he actually does have a knot, he always thought that was bullshit. His cock's not as thick as he's used to, but longer, strangely tapered at the tip.
Stiles' hand works the length of it, moving easily over that already-slick flesh, while the other hand wraps around the softness of the knot, testing its texture and its girth, getting a feel for it.
He's never wanted anything as much as he suddenly wants to fuck into Stiles, feels that need start burning him from the inside out, every instinct screaming for his obedience to himself, to his desire. Stiles' body is flushed, warm because Derek made it warm, so naked, so hard, balls hanging heavy, cock thick, slit beaded already with precome, so turned on just from touching Derek. Stiles wants him, would let himself be rolled and taken and filled, Derek could do it, he could—
His mind goes a sudden, terrifying blank, occupied only by the thought of mounting, fucking, having, knotting, claiming.
He pushes it back, takes a shuddering breath, and sits up. Stiles shifts, giving him a little more room, scrambles over his outstretched leg until he's kneeling between Derek's thighs, still working at Derek's cock. He seems oblivious to Derek's struggle for control, but Derek already knows that the risk wouldn't make him stop, anyway; he trusts Derek, trusts Derek's mastery of himself, sometimes more than he should.
Derek shifts closer, ignoring Stiles' grumbled complaint as Derek's body blocks out some of the light from the window. He's sure he can offer Stiles something more than an interesting view and a hands-on anatomy lesson. He licks at the line of Stiles' jaw, nips at the delicate flesh of an earlobe so, so carefully. Stiles' mouth is already open, and when Derek licks at his lips, flicks his tongue inside, Stiles only opens wider, moans, his hips jerking forward as he looks for friction and finds only air. Derek whimpers, mouths at the long line of Stiles' throat, laves it with his tongue, scrapes the length of his canines against it like a promise. His hands palm the wings of Stiles' shoulder blades, but he's careful with them, ginger almost, because every impulse is screaming at him to throw Stiles into the sheets and just take him, and that's not what this is.
He'd call it an animal instinct, but a wolf's courtship is gentle, solicitous, tender; this need to take and claim is entirely human.
"Derek, fuck, I need you to—"
Whatever it is, Stiles doesn't finish, and Derek wishes he had the voice to harass the rest of that request from Stiles' lips, but it's kind of nice, too, having an excuse to be completely silent the way he often wants to be as a human. It doesn't matter, anyway; Stiles just moves, instead, taking what he wants, and apparently what he wants is to straddle Derek's thighs, not quite close enough for their cocks to brush together. Derek wraps both arms around Stiles' waist purely on instinct, to help him secure his position, but Stiles doesn't seem worried about it; he buries one hand in the thick ruff of fur at the back of Derek's neck, as if to steady himself, and his other hand is stripping harder, faster, up and down the length of Derek's cock.
Derek's not going to last long like this, he can already tell, but he doesn't mind. He has Stiles naked on top of him, all sweat and desire, and Stiles is the one doing all the taking, is the one who truly understands the beast inside both of them.
That's why his mouth is at Derek's ear, and he's pulling on Derek's fur, and he's whispering, "You're so beautiful like this, so powerful, so controlled, you're mine, aren't you Derek? We're going to do this again, you know, can't believe you've been holding this back, were you embarrassed? Did you ever think about it? Did you ever want me, like this, down on all fours, just mount me and fuck me and put that fucking knot in me? God, Derek, I want to see you come like this, see how big that knot gets; we'll start practicing, so I can take it, I want it so bad, I want you."
Derek's hands slide down a little, his claws curling against the base of Stiles' spine, and his other hand slips lower still, careful, a single extended finger just pressing, insistent, against Stiles' asshole. The tip of his claw, thankfully thicker and more blunted in this shape than in a Beta shift, curves along the delicate skin of Stiles' perineum and makes him shudder, hard, his cock jolting without being touched.
Stiles gasps against Derek's mouth, squirms a little closer so his hard, neglected cock rubs against his own wrist as he tugs at Derek's cock almost frantically. Derek arches up into it, as much as he can without dislodging Stiles' weight, pressing his hips up again and again, insistently, seeking a tighter, wetter friction.
"We're gonna do that, we're gonna do everything, god, I'm going to fuck you like this too, hold onto your hips and throw your tail over my shoulder and fuck you until you literally howl, and that sound you made just now better not have been a wolfy snicker, Derek, I swear to god, because next time I'm gonna suck your cock and I need to pay attention so I know what to be prepared for so fucking stop laughing at me and come, you asshole."
Stiles' hand tightens on him ruthlessly, an even more insistent demand, and Derek is helpless to do anything but obey, comes with a force and volume that surprises even himself. Most of it splashes against Stiles' bare chest where he's curved into Derek's body, watching like he's recording the results of a really sexy science experiment. The knot stiffens and swells, but—
"I can totally manage that," Stiles says, almost to himself. He grins as he wraps his hand around the knot and gives it a squeeze, like he's trying to imagine what it would feel like inside.
It feels fucking incredible to Derek, and he can't hold back the embarrassing sound he makes as he starts coming again, thumping back down to the bed, unable to hold himself up anymore. He feels completely drowned beneath the wave of pleasure that rolls through his body, the scorching heat of it, the way his muscles twitch and jump without conscious thought, but he doesn't mind that loss of control, either, when he's safe in Stiles' hands.
Stiles just rolls down with him, hovers over him and watches him come again, and again, slides his fingers through it and wraps a slick hand over his own cock, working it fast and hard right away, like he's not planning on drawing it out.
"So good for me," Stiles says, kissing Derek's mouth again, flicking his tongue around the wicked curve of a canine tooth. "I've thought about this all the time, you know. Since the first time I saw you in your Alpha form — yeah, don't look at me like that, I was seventeen and you were featured in a variety of my more physically improbable fantasies, don't act like that doesn't turn you on."
Derek huffs under his breath, but mostly because he's pretty sure the look he was giving Stiles was actually blissed-out and vacant, not accusing. He's more or less gathered his scattered senses back to himself now, though, so he reaches out for Stiles' hips, tugs Stiles into a new position, not straddling Derek's hips anymore but perched instead on the lowest stretch of his abdomen, on top of Derek's cock. It's still extended, knot still swollen, and when Stiles settles himself on it a little more firmly — pulling his own ass cheeks apart so Derek's cock can rest between them, squeezed between Stiles' ass and Derek's own stomach, Jesus — it twitches and he comes again, messily, between them.
Not that Stiles seems to mind. He's already dripping with it, slow streaks running down his chest and stomach, but he's ignoring it all, focused again on himself and his own pleasure, whimpering and whining beneath his breath as he strokes himself. Derek wants to help, but he knows his hands would be too rough, pads like sandpaper on flesh that delicate. Stiles leans forward, searching for a new position, and finally snugs himself tight against Derek's body, rubbing their cocks together at first, coaxing one last weak ejaculation from Derek — he regrets all the awkward talks nobody ever gave him about the powers of werewolf physiology, holy fuck — and then wriggling up higher. He drags his dick through the soft fur at Derek's belly, the same spot he'd buried his fingers in at the start of the morning.
He braces himself with his hands on either side of Derek's chest and thrusts hard, a constant stream of sound falling from his mouth but only some of it even remotely counting as words. He seems to be pleased by the texture of fur against his cock, the heat of Derek's body, the sprawl of Derek beneath him, splayed out and used up and—
"Fuck, fuck, fuck," Stiles chants, and he fists a hand at Derek's nape again, squeezing his eyes shut, looking almost pained. "I can't— I'm not— this isn't enough, I need more, god I need to get off—"
Derek nips at his mouth, like a warning to stop talking, and then he wraps his hands around Stiles' back and flips them both over, pushes Stiles' back down into the mattress and rolls his hips down, hard, even though his own cock is finally subsiding. Stiles actually shouts with the thrust, mouth open against Derek's cheek, and for a moment Derek's worried that he's hurt, but then he's sobbing Derek's name and begging, so Derek does it a few more times, testing, trying not to take things too far for a human body.
"I'm not gonna break," Stiles snaps, and thumps a fist against Derek's shoulder, but then he adds, "Okay, maybe I will, maybe that's entirely possible, but it'd be worth it, just make me come."
He's gotten like this before, just in the course of... well, their more normal sex life, if it could be called that. Sometimes he gets too wound up, too excited, so intent on chasing his orgasm that he chases it away, and then he gets frustrated, and things go downhill from there. Usually Derek has to slow it down, begin again from the start and get Stiles to relax a little before he can finally let go. But Derek doesn't even know his own body well enough right now, much less how it fits to Stiles', and he's afraid to touch, worried about the roughness of his hands, the coarseness of his fur, the easy power of his jaw. Stiles has always been the one to ask for what he wants, to push for more, and Derek has always relied on his own ability to ask Stiles what he wants, how he wants it, what feels good and what doesn't. He's muzzled now, in a body not built for the tender, slow build that usually gets them through this kind of situation, and he's frozen with indecision while Stiles squirms beneath him, spitting out pleas and curses like an angry cat.
So Derek does what he knows this body is good at, opens his mouth around Stiles' throat, pins him to the mattress with a warning growl. He gives himself a moment to enjoy the rush of satisfaction when Stiles goes still and limp, makes a high-pitched sound between gasped breaths. Derek closes his jaws until his canines press hard into muscle, just shy of pain, a warning to stay put, and then he lets go, shifts further down the bed and clamps his hands around Stiles' hips, just firmly at first. When Stiles presses up into it, asking for more, he squeezes tighter, hard enough to leave bruises. Stiles sighs, the muscles in his stomach relaxing a little, something in him satisfied about being held in place.
He folds himself down over Stiles' pelvis, and avoids the butt-sniffing joke he can already feel coming by thrusting his cold nose right beneath Stiles' balls, pushing them up at the same time he dives right in against Stiles' asshole with his tongue. He figures if he has any real advantages when it comes to sex in this body — aside from Stiles' apparent obsession with the new shape of his dick — it's that his tongue is long, powerful, and dexterous.
He knows drawing it out is the opposite of what Stiles wants from him, so he files the idea of hours-long oral away for another day, and stages an all-out assault on Stiles' anatomy. The strokes of his tongue are strong, sloppy, and wet, and he moves quickly from one target to the next, probing at Stiles' hole, licking broad stripes around his balls, drawing the whole sac into his mouth and letting Stiles feel his teeth. He's obviously on the right track, with the way Stiles progresses from silence back to whimpered curses, from fidgeting to almost thrashing.
Stiles is saying, "Please, please, please, Derek, please—"
The words choke off entirely when Derek turns his attention to Stiles' cock, licking a broad stripe up the underside, wrapping the length of his tongue around the circumference, drawing the whole thing into his mouth ever so carefully past sharp teeth, and flexing the strongest part of that muscle down the entire length at once. He can't suck, his mouth isn't made for it, but he wraps his tongue around Stiles' length as much as he can manage, makes sure his upper teeth are out of the way, and then loosens his grip on Stiles' hips, gently urging him to thrust. Derek has a long muzzle, tongue, throat, and he can take in a lot of air through his nose; he's reasonably certain this is going to work. Probably.
Stiles just stares down at him, at first, sweaty and wide-eyed, his hair in complete disarray, and now he's the one who looks like a wild animal, unpredictable and savage and completely at home against the sheets, in this bed, where the monsters curl up and comfort each other in the night.
He says, "Derek," and his voice breaks in the middle, and then his hips push up, slow and smooth.
Derek takes it, like a gift, and Stiles pushes in again, and again, faster and deeper. When the root of his cock bumps against Derek's upper incisors, he only hisses like it's surprising but not necessarily bad, and makes a strangled sound as he thrusts his hips up again. Derek is perfectly comfortable, is reasonably sure he could actually do this for hours, adds that to his mental list of things he wants to try later. It's turning into a surprisingly sizable list; he feels stupid for never even allowing himself to think about this, about how it could be. He has other concerns to deal with now, though, because there are tears leaking from the corners of Stiles' eyes, and he's arching himself up off the bed entirely in an effort to get more, go deeper, and Derek isn't sure this is going to work. He might have to change back, finish Stiles in a way he knows how, come back to this later.
He starts to pull back, but Stiles makes a noise like Derek's killing him, curls his body up just enough that he can grip flesh and fur on either side of Derek's face, holding his head in place. Stiles' whole body is quivering with the strain, every muscle clenched painfully tight, hips still rolling up into Derek's mouth, and Derek growls, low and deep, frustrated that he can't give Stiles what he wants.
Somehow he does, though, because the growl rumbles through Derek's skull and Stiles' cock and Stiles' orgasm hits him like a bullet, knocks him onto his back on the bed as his come hits the back of Derek's tongue. Derek feels the release almost as keenly as Stiles does, the relief of it, feels absurdly proud of himself for coaxing it from Stiles' body. He lets Stiles' cock go gently, when it's over, licks it quietly clean as it finally begins to soften. He sits back on his haunches to admire the fine mess that's left of Stiles, the way his heaving chest slows, his unfocused eyes staring at the ceiling, his slack mouth and out-flung arms.
Derek wants to touch him, careful and slow, to gentle him after his hard-won climax, so he pulls the wolf back inside himself, puts on a more familiar, softer skin.
He settles down again quietly, stretches himself out at Stiles' side and spreads a broad hand against Stiles' stomach. That skin is still tacky with his own come, and he'll have to get up in a minute, get something to clean them both off. For now it can wait, though, because Stiles blinks at him slowly, grins a dopey grin, and says, "Have I told you you're my favorite?" It's a little slurred, but Derek can make it out well enough.
"I'd better be," Derek says. He tries to sound gruff, but he can't help his own stupid smile, feels it stealing across his lips without his permission.
"You seriously never thought about that before?" Stiles asks, his tone dubious. "Seriously?"
Derek shrugs, one-shouldered, unconcerned. Sometimes he doesn't think things through the way he should; sometimes Stiles over-thinks things he shouldn't bother with in the first place. It's part of why they fit together. "I never let myself, I guess. It seemed like too much to ask for. Even from you."
Stiles snorts. "Have you ever known me to say no to a crazy sex idea?"
"That's half the problem," Derek says, and laughs at the indignant look on Stiles' face. "I can only deal with so many sex-related trips to the emergency room per year. One of us has to show a little restraint."
"Restraint is for the weak," Stiles says. He looks at Derek like he's contemplating moving just enough for a kiss and isn't sure he's up to it yet; Derek rolls his eyes and leans in obligingly, meeting Stiles' mouth, saying a fond good-morning with his tongue.
"I'm willing to concede you were right in this particular case," Derek says, against his lips, and then he pulls back and rolls to his feet, padding toward the bathroom to fetch a towel or something while Stiles loudly crows his victory. Derek's found it's usually best to be leaving the room any time he admits Stiles is right, just so he doesn't have to listen to the gloating.
He's overdue for the laundry this week — supernatural mysteries always throw off his schedule — so he pulls the hand towel off the rail, wets it in the sink, gives himself a bit of a scrub-down and rinses it off again before he takes it out to Stiles.
"But if you had thought about it," Stiles says the moment he steps back into the room, as if there's been no pause in the conversation, "what would you have imagined doing?"
Derek hums thoughtfully as he runs the towel over Stiles' throat, down his chest and stomach, over his cock, between his legs, across all the soft and vulnerable parts of him. He thinks about that place in the woods with the bright flowers and tall grasses, thinks about Stiles' weight on his back, Stiles' vulnerable body beneath his claws, all the things that Stiles whispered into his ear, and all the things he thought of himself, behind the silence of his beast's tongue.
He tosses the towel aside, tumbles Stiles back into the sheets, and growls, "Everything," with all the greed of a ravenous animal.
art by Nordreys