It first happens after Stiles saves him from a vampire kiss. He puts his hands on Derek's shoulders and shoves him a little before gripping him hard, and he's panting, breath stuttering and sour, lips quivering; his eyes are wide and Derek can see them shine almost gold when they hit light here and there. He licks his chapped lips and lets his eyes roam all over Derek, as if he were checking him for visible harm, for injuries that won't be there because unlike Stiles, Derek can heal from almost anything. He breathes out, "that was a close one, big guy, let's get you the hell out of here." and the words trail Derek's extremities, liquid and warm and low, until they are lying at the base of his spine, and are resting right in the center of him, tightly inside his gut, heavy.

And Derek, Derek might be a little drowsy, maybe still a little under the kiss' influence, so when Stiles puts his hands all over him -under his arms, and on his waist, and just the faintest little bit on his chest for a little moment- Derek flutters his eyes, because it feels... good. So good.

"Stay with me, man," Stiles tells him, and he sounds like something Derek wants to rub himself raw against, like something he wants to lie back on.

And when he cranes his neck a little and looks up at him, he catches the slope of his nose and the bow of his lips and the length and density of his eyelashes on the dim light and thinks oh.

And then everything goes dark.

When Derek wakes up hours later at Deaton's, the man working on neutering a cat a few feet away from him, memories come flooding back, and he dismisses the entirety of the Stiles thing, blames the whole thing on the kiss, on their bites when they abducted him, and stops thinking about it right then and there, because Stiles is... Stiles. Just: mouthy and obnoxious and-

"-helpful," Deaton interrupts his thoughts, not even looking at him, "you should say thanks to Mr. Stilinski. And Scott. He worked out a truce with the kiss."

"I will," Derek grunts out, because that's true too, and hops off the examination table.

And that's meant to be it. A one off, a lone instance under extreme circumstances.

But, because this is how Derek's life works, it isn't.

A week or so later Stiles comes knocking at his door, backpack on him, hair tussled, eyes lively, and Derek's grip on the door frame tightens enough that his ears can pick up the tinny sound of the wood creaking under his hand, can feel a small splinter lodging itself on his palm, and he thinks oh, oh shit.

Stiles gives him a lopsided smile, asks him, "are you gonna let me in or what, man?", gesturing at Derek expansively with his long, nimble fingers, and Stiles' shirt is maybe a little small on his growing frame, because with the movement of his arm it shows a sliver of skin, a little of pale stomach, and Derek has to clear his throat.

"Yeah, sure." He says, aiming for dispassionate but not quite getting it right, as he moves a few inches to give Stiles room to come inside.

Only, it's apparently not enough room because Stiles bumps against him. And it's just a minute graze of his shoulder and his bony elbow, and he feels a little sore for a few seconds there, but still. His stomach feels like it's plummeting, like it's being overcome by a sort of seasick motion without him even moving, a thing that's so juvenile Derek wants to groan and cover his eyes.

Oh, fuck.

"Yo, Derek, you coming?" Stiles asks, then, turning a little to look at him with raised eyebrows.

Derek says yeah, low and kind of unpleasant, and then takes a step towards him and-

-fucking trips. Over nothing.

Stiles stays for a few hours, has a few theories about the Nemeton that he wants to run by him, wants to 'compare notes' ("you still have Peter's computer, and I've seen your books, man, you can't keep holding back on us."). He does a lot of talking, and a lot of pointing at words in old, stained books of dubious origins that smell like "cat pee, Stiles, really?"

"Shut up, we work with what resources we have, man."

Derek snorts, and Stiles rolls his eyes at him and goes right back to it, all rushed words and pointing at old looking words and drawings in yellowed pages, and Derek goes right back to trying to focus on what he's saying.

(They are sitting in the same couch, side by side, knees touching, because Derek hasn't gotten around to buying much furniture-)

Focusing. On Stiles' words. About the Nemeton.

(Stiles gives off heat, and a fresh clean scent, a little fresh from the outside, with tones of body spray and a bit of sweat-)

Fuck.

"I'm gonna get something to drink," he says then, interrupting Stiles mid sentence, which earns him a glare.

From there on it's pretty much like a downwards spiral, and Derek can't find anything to hold on to. He's losing his balance.

More than metaphorically sometimes apparently, because since he's started noticing Stiles'... what? Objective attractiveness? Appeal? He's tragically been suffering from some sort of regression, like his actual teen years hadn't been enough of a pain, and like the universe hadn't already had its fun with him.

"Aw, dude," Stiles hisses at him, rubbing his arm where Derek accidentally clawed him by trying to stay upright after catching sight of a cluster of moles on the nape of Stiles' neck and barging into a desk (and why do they have to keep meeting on school grounds? Derek is going to get arrested again one of these days).

Scott's looking at him with an expression that's half amused and half admonishing, and Derek could lock himself inside his new apartment and never come out again.

"Sooo," Isaac drawls one day, fiddling with the radio dial on Derek's car while he's taking him to school ("you should give it a try," Scott had said, face stern and eyes serious, when he came back, "make amends, right your wrongs, reconnect; that kind of stuff"), "Stiles, huh?"

"No," Derek replies, hands tightening momentarily on the steering wheel. He can feel his own heart beat faster, can feel it echoing on the tips of his fingers and can hear it like a thundering, overpowering noise, and this is so ridiculous.

Isaac smirks at him, settles on a radio station that's all apathetic alternative music and Derek would change it, but Isaac's looking happier in his presence than he has in a while and he doesn't want to blow it.

"You have a shot, you know," Isaac tells him, then. "Stiles likes them intimidating and out of his league."

"Isaac, shut up."

"I'm just, you know, saying. For your future reference." He says then, fixing his scarf and trying to look like the very picture of innocence.

(For all that it's one of the most frankly embarrassing moments he's had to go through since puberty, discussing his possible feelings for a teenaged boy with yet another teenager, there's still a warm something running through him when Isaac smiles at him before getting out of the car when they reach the high school. Something that feels like an inkling of possibility, like contentment. Like pack.)

Stiles ends up tagging along with him on a reconnaissance mission a few days later. There's a group of shifters on town, not werewolves, not killers by their eyes or scents, omegas all of them; they aren't particularly suspicious, but they haven't sought Scott yet, and that's what tradition mandates while on another Alpha's turf, so they are checking them out to avoid unpleasant situations.

"Murders. To avoid murders. They could be a bunch of murderers." Stiles states, nibbling on the plastic tip of his hoodie, eyes narrowed.

"They have a baby with them." Derek points out, skeptical, because someone has to, before Stiles works himself up, or convinces himself of some insane theory about these guys.

"And murderers don't have kids?" Stiles looks at him then, raises an eyebrow. "Because I could name at least one murder happy motherfucker who had kids. And we know him. Personally."

Derek doesn't have time to visibly react to that before Stiles' eyes widen and he starts waving his hands on his direction, almost smacking his arm; he spits out the string and Derek watches as it falls, forlorn and damp, trying to avoid thinking of Kate Argent. Daughter of a murderer. Child of a murderer. And a murderer herself.

"I'm so so sorry, dude." Stiles stammers, "I'm such a dickhole. Fuck, fuck."

And at Stiles' upset voice tone, he looks up at him, locks eyes with him, but not without first catching him biting his lip vigorously. Stiles looks upset and he smells nervous, his heart rate fast and stumbling and deafening.

Derek's own heart plummets and he frowns. Stiles has to know Derek won't just attack him, won't wolf out on him, 'unleash his wrath', or whatever the hell; has to know that he can put his foot on his mouth, and fuck up, and Derek still won't harm him. He has to, by now.

Derek remains silent, lips pursed, not really knowing what to do or say. Stiles puts his hand on Derek's arm, after a while, wraps it around his bicep and squeezes, eyes never leaving his, cheeks flushed, a few beads of sweat pooling on his skin, smelling of awkwardness and teenage-hood, and embarrassment.

"Are you okay, man?"

Stiles' heart is still deafening and irregular, and like that -with Stiles' fingers on him, tight and secure and warm- it dawns on Derek that Stiles isn't afraid of Derek's reaction. That he's actually... Remorseful? Worried about him?

"Yeah," Derek says then, and debates shaking the hand off of him, or staring at it until Stiles takes it away himself; he ends up getting a little caught up on the paleness of the inside of Stiles' wrists, getting distracted by the pronounced veins there. When he reins himself in he mutters a little, "asshole" under his breath, and it makes Stiles smile and finally take his hand off.

"Pot, kettle," he says, motioning at them both. And Derek feels lighthearted and silly, and like replying. Like letting this escalate into something childish and over the top, because they are good at this; Derek is good at this.

But that's when they hear a blood curling scream from the house they're supposed to be watching over.

"Fuck," Stiles says, and turns around to get out of the car.

Derek does the same.

Only to bang his head right against the car window.

"Dude," Derek hears Stiles gasping at him.

Fuck, he thinks, fuck fuck fuck.

"So they weren't evil murderers," Scott says when Derek calls him and puts him on speaker, holding a bag of ice to the bump on his forehead that's taking entirely to long to fade away. He doesn't sound surprised at all. In fact, Derek can tell the distinct sound of buttons being jammed in the background, along with tinny explosion sounds and Isaac's grumbled curses.

"No," Stiles says, lolling his head on the headrest until he can glare at the phone on Derek's hand. "Apparently they are just assholes who like scaring the shit out of innocent people for no fucking reason at all."

"I don't know, man, you were parked outside of their house at fuck o'clock spying on them. That sounds like a pretty solid reason," Isaac butts in.

"Shut up," Stiles groans, looking murderously at the phone, as if trying to make Isaac feel it on the other side by sheer will and intensity. "They could've been dangerous."

The silence on the other end of the line actually speaks louder than any words Scott and Isaac could've said, the mocking oh, really? There is almost palpable and Derek can't help but smile at it and at Stiles' spluttering indignation.

"One of these days some fucking stepford looking family will come to town and kill us all because you keep not paying attention to what I say." Stiles says, getting close enough to Derek to kinda righteously spit that out at microphone.

Then he looks up at Derek, eyes roaming around his face, a short few inches apart.

"And you should maybe stick up for me here, since all this stake out thing was your idea." He says then, and his breath touches Derek's nose, lips, cheek.

("Yeah, okay, bye guys." Scott says then, rushed, before hanging up on them.)

What's a good way of saying, I always pay attention to what you say, even if I think what's coming out of your mouth is ridiculous?

The next time they're alone together, Stiles is at his apartment again, sprawled on his couch like he owns it, chewing on a cheap looking pen, and reading some printed pages that make no sense to Derek.

When he'd come knocking earlier, he hadn't even offered an explanation to Derek at all, had just smiled at him and shouldered his way inside, assertive enough that Derek had stared after him (body fucking tingling where they'd brushed) with raised eyebrows in inquisition.

That hadn't gotten him an answer, though. Stiles had just walked to his couch and made himself at home; had flung his heavy backpack to the floor, and had started taking books, notebooks, and single sheets of paper out, spreading them on Derek's new coffee table as if that was something they'd always done.

You have done this before, though, a voice inside Derek's head spoke then, clear and sounding like a mixture between both Cora and Laura, casually invaded his living space. So Derek had just grunted at him, barked at him to not put his fucking feet on the table if he wanted to leave with all his limbs intact ("you have to stop posturing," Scott had said to him, with the same serious concerned and responsible Alpha face he used when giving him advice, a few weeks ago, "we're meant to be family").

"Okie dokie," Stiles had replied, cheeky and fucking smirking at Derek as he took his shoes off, and lied down on his couch, prints and pen firmly in hand.

Derek had sighed then and started making his way to the kitchen to started on dinner, because that was what he was gonna do before Stiles had interrupted his routine, and he still had to eat.

"Are you staying for dinner?" He'd asked over his shoulder, as he kept on walking.

"Hell yeah." Stiles had said, fist bumping.

Derek had cracked a small fondly amused smile then, contentment sinking on his bones.

And then he'd promptly walked into the kitchen doorway.

"Dude, Derek, again?"

He's slicing up some carrots when Stiles slides up to him, resting his hips on the counter and his back on one of the counters (the one with the glasses, he thinks, glad that he won't have to reach for anything there in the near future), hands at each side of him, and a thoughtful expression on his face that makes Derek weary.

"Do you need anything?" He asks, pouring as much sarcasm into the question as he can.

"When are you gonna kiss me?"

Derek cuts his finger.

Stiles curses and moves on to take Derek's hand between both of his, and starts examining the cut with critical, worried eyes, sucking on his bottom lip with a look of concentration that makes Derek's stomach flutter like it's rebelling itself, preparing to liquify itself and exit Derek's body through his very pores.

"Were you always this clumsy, man?" Stiles blurts, while he opens the tap and drags Derek's hand under, the cold water washing the blood away from the cut that's already healing. "Cos if you were, it's kind of a miracle you made it past puberty."

"Pot, kettle." Derek replies, hoarse, as the stinging recedes and numbs until it isn't there anymore and his finger is entirely healed, skin sensitive and unblemished.

"I'm as graceful as a swan," Stiles says as he closes the tap, and lets Derek have his hand back. Derek snorts at him and Stiles rolls his eyes. "Whatever."

Derek rolls his eyes back at him, but he knows he's flushed, can tell that Stiles can tell he's stalling, is letting him get his bearings.

"Okay," Stiles says, after a few seconds, "so..."

"You're seventeen." Derek states, because it's the one simple thing he can say, the one moral qualm he has and that nags at him, eats at his conscience when he's jerking himself off fast and rough and thinking of Stiles sucking on his hoodie string with full, pink lips.

It's easier than saying I fall hard and fast and I don't think I can take it if you're in it for different reasons than me, I don't think I can do the having you for just a little while and then letting you go so you can go to college and experiment and live up to your potential and grow up to be the man you're meant to be with someone better than me next to you; easier than I don't think you're ready to have me trailing after you like a than saying I think you're gorgeous, and the best damn thing that's happened to me in years after getting Cora back.

"Only for a few months," Stiles says back, and then he adds, eyes going determined and grave: "Look, if it's just a physical thing and you don't want to act out on it, that's fine by me. I won't pressure you, man. I just thought..."

And he stops there. Closes his mouth like he's said too much, but he hasn't said nearly enough for Derek, he tries to communicate him a silent go on through an aborted motion of his recently healed hand, and Stiles' eyes flicker between it and his eyes.

He sort of rubs his hand over his cheek, and then over his jaw, before dropping it to the kitchen counter, and saying, "I just thought that maybe we were on the same page, feelings wise."

The words come out tired, sad. They tug at Derek's heartstrings, play him like a violin, leave him raw and tender, and aching to reach out to Stiles and finally touch; touch his face, and his neck, and his arms, and maybe even the dark trail of hair from his navel on downwards.

"What," he starts, takes a step towards Stiles, studies his face, the tense set of his jaw, the speckles of pure gold in his eyes, the worry lines on his forehead, "what do you feel?"

Stiles blinks a few times, stares at Derek's feet, then back up at his face, and his heart rate escalates.

"I," Derek takes another step towards him, almost against his own better judgment because he knows all the reasons why this is an awful idea, has been beating himself up with them for longer than he cares to admit, but at the same can't stop feeling compelled to move forward, to move closer to Stiles and Stiles' voice and his scent, and this possibility, this one possibility that maybe Stiles is in it for the same reasons as him, for the same overpowering load of feelings he carries around. "corny things. Really corny things. I look at you and get lost in your eyes, because what color are they even? And I get so upset over your stubble and your jaw, and your arms, and your stupid, washboard, defined as fuck abs. And the- the fact that you humor me when nobody else does. That you listen to me when there's no need, that you take care of me. That you do shit for me that you wouldn't do if it was just up to you. That I have a stupid ten year plan, and it includes you everywhere, like a permanent fixture. It's the worst, Derek. You don't even know."

"I do," he assures without really intending to, taking another step until he's flush with Stiles, backing him up against the counter, chests almost touching.

"You do?" Stiles asks, breathless, looking into his eyes, leaving his lips parted, hand coming up to waver uncertainly next to Derek's arm.

"Yeah," he nods and is about to move in to finally kiss Stiles when his oven timer starts ringing-

-and Stiles kind of flails with his entire body, managing to hit Derek on the nose, trip over his own feet and make Derek stumble himself, which results in the both of them falling to the floor; Stiles on top, jabbing Derek with his elbows, and almost kicking him on the groin.

"You have to be fucking kidding me," he grunts.

"Oh, fuck it," Stiles grunts back and goes for the kiss, anyway.

Even with the awkward angle, flare of pain on his back, and the faint burnt smell coming from the oven, it's the best kiss Derek's ever had.

"I haven't made you trip or bump against furniture in like months, man," tells him Stiles jokingly the night of his eighteenth birthday when they're lying on Derek's bed, sweaty and spent, brushing his nose against his naked shoulder, wrapping one leg around him. "should I worry that I'm losing my touch?"

Derek rolls his eyes, but lets Stiles hide his cold feet under him, presses a kiss on his damp hair, hugs him to his chest.

"Shut up, Stiles."

"Like that's ever worked, big guy."

Derek smiles.