Stiles is in the middle of making notes on the benefits of using Celtic Runes over Ancient Chinese Hanzi, and whether he can blend the two into one kick ass ward when Derek comes home, the loft door loud as he pulls it open.
“Oh, good, you’re back.” Stiles greets, Derek closing the loft door behind himself. Looking up, Stiles smiles at Derek, giving him an appreciative once over in his short shorts and hoody. There is nothing more attractive than Derek's thick thighs encased in ridiculously clingy short shorts. Derek's thighs were the reason short shorts were invented. Forcefully dragging his eyes up to Derek's face, Stiles smirks at Derek's raised eyebrow about being blatantly checked out. “Perimeter all clear?”
"Story of our life." Stiles starts cleaning away everything he was working on, knowing the smell of the herbs makes Derek’s nose itch in a way only magick can.
“There a reason you’re playing witch in nothing but one of my shirts?”
“I have underwear on, big guy.” Stiles lifts the hem of one of Derek's ridiculously oversized shirts up enough to flash Derek a pair of neon green briefs.
“I think I’ve just been deafened by how loud those jockies are.”
“What was that? I can’t hear you over your underwear.”
Stiles pulls a face at Derek. “Oh my god, you’re so funny. You should be a dad with those kinds of jokes.”
Derek smirks, "Maybe I will be."
Stiles gives him a look, letting a moment of silence weigh heavy between them. "I'll hold you to that one day."
Nodding and smiling, Derek heads to the kitchen to get a drink of water. “What are you making anyway?”
“I’m trying to figure out a type of warding charm combining two different language systems. It should, in theory, give any supernatural being whose DNA isn’t in this charm a headache so severe it actually causes temporary brain damage, rendering them incapable of moving as long as they are within range. And by drawing a specific symbol in human blood it'll make the brain explode. But the seal is proving to be an absolute bitch.”
“...My DNA is in there, right?”
“It won’t be if you keep making fun of my underwear.”
“Have I mentioned lately how the colour neon green really compliments your eyes?”
“Suck up.” Stiles scoffs.
Derek waits in the kitchen until Stiles is finished for the day and puts the herbs away in a lead lined, warded box; the wards erasing the scent of anything placed in it.
Once the box is locked closed, Stiles places it on one of the lower shelves of their massive bookcase. Stiles is acutely aware of Derek's eyes on him, making a bit of a show in standing up, flashing Derek a hint of neon green. "Like the view?"
"Still wondering why you're only wearing a shirt. And my shirt at that." Derek steps around the kitchen counter, folding his arms across his chest and crossing his ankles as he leans back against the bench. He squashes the smirk that tries to form at Stiles' eyes predictably going to his thighs.
"I put a load of washing on, and all of comfy clothes were in that load so I borrowed one of your tops. That a problem?"
"Quite the opposite."
They just watch each other for a bit after that.
Stiles admires the strength in Derek's legs, how much hairier they've gotten since Derek evolved. Which leads to Stiles' eyes travelling up Derek's body, eyeing up his hoody and the body hair he knows is hiding beneath it. Said hoody is doing little to hide the mass of muscle in Derek's arms, shoulders and chest, Stiles suddenly aching to be wrapped up in those arms. Pretend he's safe for a little while. Pretend that every time something goes wrong he isn't the one who has to figure it all out and make everything right again.
Derek watches as Stiles' eyes travel up his body and decides that turn about is fair play. He starts at the hem line of his shirt, smirking at the neon green hiding beneath it. Stiles' legs are toned, nothing but strong, lean muscle from all of his running. And surprisingly hairy considering the kid can't grow facial hair to save his life. Derek flicks his gaze up Stiles' arms, from long fingers to thin wrists to elbows to shoulders, eyes tracking the moles dotted along the way.
They eventually lock eyes, and end up just looking at each other from opposite sides of the loft, silent conversations being had and no doubt unsynchronized.
Keeping his gaze locked with Stiles', Derek crosses the room. He stops just short of Stiles, lifting a hand up to cup Stiles' cheek. Watches, as Stiles brings both of his hands up to hold Derek's hand in place, pressing his cheek more firmly into Derek's palm.
Derek's heart aches, and he can tell that Stiles' is aching too from the furrow in his brow. Raising his other hand to Stiles' free cheek, Derek gets Stiles to look up at him; to meet his gaze once more. With a kiss to Stiles' forehead Derek leads the boy to their bed, undressing him and pressing his lips to every inch of skin that is exposed. Stiles removes Derek's clothing at a more hurried pace, placing rushed kisses to shoulder, pectoral, abdomen, hip bone, and thigh.
Derek moves away from Stiles slightly, forcing the other to slow down. With gentle nudges he gets Stiles to lie down on his side, Derek spooning in behind him.
Stiles pushes himself back into Derek's chest, greedily stealing the excess heat of the werewolf. He tilts his head back onto the werewolves shoulder happily when Derek wraps his arms around Stiles' chest and waist.
Derek buries his nose in Stiles' neck, arms gripping tighter at the combination of their scents from Stiles wearing his shirt all day, his nose itching slightly at the lingering smell of dried herbs.
Stiles knows that Derek gets off on smelling their mixed scents. Knows it has to do with being a werewolf. And Stiles gets off on Derek getting off on the smell of them together. It's weird and fucked up, but it works for them. Stiles buries his face in the pillows, arching his neck so Derek can have free reign.
Derek rubs his nose up the nape of Stiles, kissing the skin then licking broad stripes right up into Stiles’ hairline. Stiles shudders, pushing his whole body back into Derek's, never admitting aloud how much he loves it when Derek licks him in odd places. How much he loves it when Derek is blatantly scent marking him. Stiles can feel Derek getting hard between his thighs, Stiles responding the same in turn.
Derek reaches over Stiles' body to gently pump the boy's dick to full hardness. Every sound Stiles makes has Derek's teeth itching to sink into flesh; to claim. Clenching his jaw tight, Derek rocks his hips forward instead, rubbing his cock up the cleft of Stiles' ass. Stiles is quick to beg after that.
"Jesus, Derek, do it, just do it already, I've been waiting so long." Stiles is going to push the matter further when he feels Derek pull away from him to reach for the lube stashed in the drawer of their bedside table. Arching his back, Stiles forces himself to relax, waiting for Derek to cross the final line between them.
Stiles shrieks with shock when cold lube is applied between his thighs and not all up inside him. "I don't think that's how that works, Derek."
"What would you know?" Derek teases, slicking his cock up then moving back to pressing the front of his body all up Stiles' back.
"Apparently a lot more than y-what the hell are you doing?" Stiles grips the hand that is on his hip tight as Derek pushes his cock through the slick between his thighs. When Stiles tries to open his legs and turn around to look at Derek, the werewolf pins his legs back together with one of his own, locking him there with preternatural strength.
"Intercrural. I would have thought with your web history that you would know what this is."
"Well, yeah, but- I thought we were going to..." Stiles stops speaking, too distracted by the feel of Derek's cock thrusting between his thighs to finish his sentence.
"Going to what, Stiles?" Derek shifts his thrusts up slightly, the head of his dick pushing against the back of Stiles' balls.
With the added stimulus, Stiles curls up slightly, his back un-sticking from Derek's chest to watch Derek's cock disappear and reappear between the milk white of his thighs. The sight of it puts Stiles in a near trance, his breaths shortening and coming out in hitched noises when Derek hits a particularly good spot behind his balls.
But it's not enough. And this sight is too good to waste.
Stiles grabs his cock and jacks himself off with the intent to finish. Derek grips his hips tighter, and Stiles smirks knowingly at his reaction to Stiles getting off on watching Derek like this.
Moving his body back, Stiles tilts his head awkwardly to share a quick kiss with Derek. He rests his head back on the pillows and shuts his eyes, trying to just focus on the sensations and slick sounds of them both. Imagines what it would be like to have Derek inside him right now, fucked full.
It's that final thought that has Stiles jerking into his palm, orgasm making his toes curl. Before he can even coax the last few drops of semen from his dick, Derek's jaw is closed around the meat of Stiles' shoulder. Stiles calls out in a mix of pain and a flash of magick, the spark in him reacting mildly to being bitten by a werewolf, setting his nerves on fire and frying his system in a blast of endorphins.
Derek gets a little brutal with his thrusts, knowing there will be bruises on Stiles' hips later but not caring in the slightest, a part of him pleased that the boy will me marked up by him.
He spills between Stiles' thighs and all over the boys balls and softening cock, Stiles still frozen in the height of ecstasy, Derek knowing that his eyes will be pitch black as the magick still burns through his system. This had happened once before, and once Stiles was in complete control of all his faculties again he had punched Derek in the stomach, lecturing him about not messing with supernatural forces like that, and in the same breath to only do that once a month 'because oh my god what an experience, Derek'.
Derek knows it's over when Stiles' body goes limp back into him, spasming with the after shocks of magick. He holds Stiles tight, not yet ready to unclench his jaw from the boys shoulder. Stiles is muttering a bunch of half formed sentences, mostly nonsense, but Derek listens to it all to make sure Stiles is completely ok.
They end up falling into a light doze like that, only waking when Stiles is finally free from Derek's bite and with a punch to Derek's gut.