"I can do this!"
"I believe you," Derek says, trying very hard to sound neutral and not at all patronizing. Stiles’ teeth aren’t sharp, but they’re still within bitey distance of Derek’s cock. Also, he doesn’t really believe Stiles, but it seems unwise to point that out right now. "But you don’t—"
"I know I don’t have to!" Stiles wiggles Derek’s cock emphatically. "We’re sort of past the whole is this or is this not misplaced obligation argument, remember?" He shifts his weight, sinking back onto his heels, and rubs the corner of his mouth absently — with the spit-slick, blunt tip of Derek’s cock.
Derek sucks in a hissed breath, nearly claws his own bare thighs.
"Besides," Stiles adds thoughtfully, "it’s not a matter of not being into it. I mean, obviously." Obviously is the angry line of his erection, bobbing gently every time he moves. "This is a mind over matter thing."
"You’re not training to be a sword swallower. It’s just a sensitive gag reflex. It’s not uncommon."
Stiles glares, grips the base of Derek’s cock harder, and licks a long, hot stripe up the underside like the brat he is.
"You’re trying not to shift, aren’t you?" Stiles grazes the underside of Derek’s cock with his bottom teeth. It makes him look like a pug, but Derek’s not going to tell him that. Not when it feels like tiny fireworks going off somewhere deep in his gut. He presses the heel of his palm down, rubbing his stomach, rubbing his inner thighs, wanting to grip Stiles by the jaw, wanting to fuck his mouth.
"Yes, I’m trying not to shift. This should concern you," Derek says. "Why don’t you have any sense?"
"I’ll give you that one." Stiles sucks a little kiss like he’s savoring Derek’s precome. "Good life choices aren’t my wheelhouse, but I trust you." He says it so easily. There’s no hint of a lie or manipulation, and it heats Derek’s flesh all over. This boy. "Even if you wolf out, you’re not going to hurt me."
"I’m calmly considering it, actually."
"Oh!" Stiles jerks him off with wet, tight little pulls. Just enough to make Derek think he’s going to establish enough of a rhythm to get things going. Then he stops. "If you wolf out when you’re naked, does your cock get furry? Does it get less furry? Oh my god. Does it get bigger?"
"I think you fabricated the gag reflex issue to keep me from shutting you up," Derek says.
Stiles’ eyes go bright and dark in a way that only ever means trouble. “Do you want to shut me up? You can cover my mouth.” He moves his hips in a way Derek is certain he’s completely unaware of. It happens whenever he starts coming up with things they should do, things Derek should do to him, things he should do to Derek. It’s like he wants friction, wants more, and doesn’t know how to get it or ask for it.
"One thing at a time," Derek says as carefully as he can. His mouth goes dry watching Stiles’ nipples tighten and a wild, pink flush creep across his chest and up one side of his throat. "Do you want to try again?"
"Yeah." Stiles’ throat clicks with a swallow. "Okay." He licks his lips and makes a sweet circle with his mouth.
Derek blows a slow breath out to keep still as Stiles guides the tip of his cock between his lips. His tongue is soft, wet, and he’s already drooling excessively. It shines at his lips, runs slick down his chin, and he swipes his thumb at it, closes his eyes and keeps going.
"Slow down," Derek says. "Go easy." It’s excruciatingly difficult to speak. As soon as Stiles gets over his latest burning need to become a pro cocksucker, Derek’s going to turn him over and fuck him into the next time zone. And he will definitely cover his mouth.
He shouldn’t think about this while he’s trying to keep still.
Stiles hums something, seems to notice that he can’t talk with a cock in his mouth, and grins around it, eyes fluttering open to shoot Derek a mischievous look that damn near pushes Derek over the edge. Stiles’ lips go thin, and his eyes widen, and he chokes again.
"Take a breath," Derek says, voice raw, cock so hard it hurts.
Stiles applies suction and pulls off with an obscene pop. He draws a great big breath, gives Derek’s cock a dirty look, thrashes an open-mouthed kiss against the crown, and goes right back to business. It’s the wrong way to overcome a gag reflex, but Derek has no interest in stopping him. There’s something beautiful about the determination in Stiles’ eyes, the way his whole body tenses when he chokes, the way it makes his mouth wetter, the way he doesn’t stop because he never knows when to stop, and wouldn’t even if he recognized his own limits.
Derek doesn’t know what to do with this kind of trust, with such a precious thing.
"Breathe through your nose. Not like that. Slowly." Derek runs his fingertips into Stiles’ messy hair. It’s so long now — always tempting Derek to grab it, to rough him up the way he would another wolf, the way the animal in him wants to. The way he does anyway, once in a while, when Stiles moves and whines like he needs it, begs with his fingers like he’ll die if Derek doesn’t fuck him harder, if Derek doesn’t bruise him with his mouth.
Derek huffs a happy noise. “You like that, don’t you?” He can tell Stiles is warring between continuing his incremental progress down the length of Derek’s cock and pulling away to mouth off. He makes a lot of noise about Derek’s teasing, but when Derek tells him how good he is, how easy it is to undo him, he gets hotter, wilder, comes harder.
Stiles’ teeth graze Derek’s shaft, and he can’t tell if it’s intentional or not.
"Relax, Stiles," Derek says. He rubs the soft skin behind Stiles’ ears, follows his hairline, works at the tension at the back of his neck and rounds his knuckles and thumbs to Stiles’ cheeks and the wet, swollen-soft skin where his lips are stretched open.
Stiles groans, blinking slowly. The fingers of his left hand climb up the outside of Derek’s thigh, start to draw lazy circles at Derek’s hip. It’s a good sign. If he settles and stops thinking so hard, his throat will relax.
Moving steadily, Stiles manages to establish a rhythm, his tongue fluttering as he works through another fit of choking, and sucks at Derek’s cock with shallow strokes.
"That’s good," Derek says, running his thumbs along the corners of Stiles’ mouth. "I’m close, looking at you like that. How do you want it? In your mouth?" Stiles whines, trembles a nod. "Think you can swallow it? Will you choke on me?"
Stiles gags, like the thought of it is too much, but he doesn’t stop. His eyes water, and when he blinks, tears spill over. Derek motions to push him away, and Stiles gives a faint headshake, and something like a growl, and strokes his hand to meet his mouth. It spreads his spit down Derek’s shaft, making it wetter again, making everything tight and wet. Stiles’ arm tenses, muscles coiling and tight, so hard when his mouth is so soft, his lips are so soft, he’s a mess. He’s perfect.
"Stiles." Derek’s thighs tense up. "Stiles." He covers Stiles’ hand with his own, shows him how fast to go, urges him to tighten his grip. He’s not as sensitive as Stiles is, he needs it rougher, wants to feel it when Stiles pulls him over the edge.
Stiles makes a triumphant noise, chokes, chokes harder, and doesn’t stop. His grip becomes merciless, burning a fiery ache up Derek’s back, tightening his balls, and then Derek’s hunching over Stiles, bracing himself on Stiles’ shoulders, digging his fingertips into the muscle there as he shouts an empty sound and comes with helpless, jerky thrusts.
It’s a lot. He knows it’s a lot, but he’s lost in it, cups the back of Stiles head and holds him there, feels the way Stiles’ mouth constricts around him as he’s swallows, gasps, gags, and swallows more.
"Fuck," Stiles says, when Derek pulls away and drops off the edge of the bed. He grabs a towel from the floor and covers his mouth, catching his drool as he keeps gagging and breathing.
"You’re okay, it’s okay," Derek says, kissing Stiles’ cheek, nosing at him. "You did it."
They’re both sweaty, sliding together. Stiles has tears on his face, and his mouth is red, and his fingers shake when he puts the towel down, keeps swallowing, working against the aftershocks in his throat.
Derek kisses him. He tastes himself, tastes the coppery heat of raw skin, wraps his hand around Stiles’ cock and strokes him off. It doesn’t take much. Stiles comes apart in his arms, sniffling and gasping and biting at the last moment. It’s an impressively hard bite at the tender skin at the crook of Derek’s shoulder — and Derek knows he deserves it, laughs fondly and runs his hand up Stiles back.
"I’m definitely going to fuck your face," Stiles gasps out sullenly, hot against Derek’s skin. He smells happy.
"Okay," Derek says. He pushes his finger into Stiles’ mouth, feeds him a smear of his own slick come, and smiles when Stiles gives a low moan and shivers with the last edges of his violent orgasm.
"Mm," Stiles says around his finger, suckling at it noisily. "Okay."