Stiles's is used to his birthday being a quiet affair with Scott, usually his dad and Melissa if they're not working. This year there's a whole party in the backyard with balloons and hot dogs and people singing Happy Birthday as cheesily as possible—namely Erica, Scott, and for some reason Isaac gets really into it. Erica makes him a cake that's a cherry vanilla abomination of fruit and frosting but tastes sooo good.

There are presents. So many presents. His dad gets him two new video games that he's been dying to play. Melissa and Scott get him movies. Lydia gets him clothes "that actually fit, you fashion disaster" and Erica gets him a sex toy that he immediately shoves back in the box and behind the couch while his dad pretends that he saw nothing. Isaac has a shit-eating grin when he hands Stiles a gift bag with a scarf in it. Boyd got him matching mittens and a hat. Jackson throws a gift card at his head and then Stiles's eyes bug and he chokes on air as he looks at the denomination.

Derek hands him a small box that he thinks contains another gift card or maybe jewelry, but he opens it to find a single key inside. Stiles's eyes shoot up to meet Derek, who's smirking, and then he has to look away before his face ignites from blushing.

He doesn't let go of the box for almost an hour.

Isaac had made very pointed comments about having a sleepover at Scott's. Stiles is pretty sure Allison's going to be there too and he doesn't want to think too much on how that's going to work out. He uses the key Derek gave him to let himself into the loft. He's somewhat amazed as the key turns in the lock. For some reason, he hadn't entirely expected it to work.

He steps inside and the bed that takes up the center of the loft catches his eyes. He can't seem to look away as he slides the door shut behind him and flicks the lock. There's a cough off to his right and Stiles startles, jumping nearly a foot in the air and turning red as he finds Derek watching him with a smirk.

Derek's coming out of the kitchenette with a glass of water but he sets that aside and crosses the floor to slip his arms around Stiles. "Hey."

"Hey," Stiles says back, and then says nothing at all as his lips are captured in a deep kiss.

Stiles melts. He loves kissing Derek. He loves being kissed by Derek—the way it makes his knees weak and his skin tingle. He leans into the kiss. His bag falls to the floor as his hands settle low on Derek's back.

Then Derek tilts his head just right and his tongue is inside of Stiles's mouth. Derek's hands slip under Stiles's clothing, one pressing against his spine and the other sliding low to grab his ass. He squeaks. He always does. He doesn't think he's ever going to get used to someone touching his ass, let alone wanting to touch his ass.

It's not as weird as it used to be. True to his word, Derek has been keeping things slow. Sort of. They've been ramping things up a bit, getting more exploratory but things have mostly stayed above the belt.

Stiles has a feeling that's going to change tonight.

He squeaks a second time as Derek breaks the kiss to dip low and grab the back of his thighs. He's lifted off of his feet and it gives him a strange sort of thrill as Derek supports all of Stiles's weight in his arms.

"You like that?" Derek tugs slightly, pulling Stiles close and making Stiles's growing erection drag against Derek's washboard abs.

Stiles shudders and presses his flaming face into Derek's shoulder. He nods.

"Later," Derek says, his voice low and husky right next to Stiles's ear, "I'll hold you up against the wall and fuck you. And I'll take my time, do whatever I want to you because you won't be able to move, just take it."

Stiles whimpers—the good kind of whimper—and nearly comes in his pants. Derek's not really a vocal person but when they're together, when it's just them and Derek's hot with desire, he suddenly seems to find all of the words he lacks at other times of the day. "Yes. Please."

The world tilts as Derek lowers him gently onto the mattress. It's a feeling that should be scary, because he's kind of falling, but Derek's arms are around him and he knows Derek isn't going to drop him. He's pretty sure the blush on his face is there to stay. Derek leans back and all he has to do is look at Stiles to make Stiles's insides squirm in anticipation.

Warm fingers slide under the hem of his shirt, lifting it up and away. Stiles raises his arms but doesn't offer any further assistance. He kind of likes letting Derek take care of him.

"Did you have a happy birthday?" Derek asks. He's smiling. It's becoming less and less rare to see Derek smile but it still hits Stiles right in the heart every time he sees it.

"I did. Thank you."

Derek peels his shirt off in a way that makes Stiles's pants too tight. Well, tighter. He knows it's just a normal way of pulling off his shirt, and on any other guy it'd be normal, boring even, but Derek makes it look like he's a stripper putting on a show just for Stiles. Then there are those abs and his muscles.

Stiles wants to lick them. He has licked them. Derek had to leave the room for a few minutes and jerk off because Stiles licked them.

Stiles grins and starts to lean up but Derek places a hand on his chest and pushes him back down onto the mattress. Derek's hands land on Stiles's fly and Stiles freezes for a moment.

They're doing this. They're really doing this.

Fucking finally.

He nods and then Derek's leaning down, pressing his lips to the sensitive skin around Stiles's bellybutton. Derek draws Stiles's zipper down and his mouth presses lower, against the waistband of Stiles's boxers. Then Derek hooks his fingers in the fabric and it's being pulled away, leaving him naked and exposed.

Derek's mouth follows the expanse of newly revealed skin, kissing Stiles's stomach and hip, bypassing where Stiles really wants it to press a kiss against his knee and then his ankle. Derek stands, dropping Stiles's pants to the side and then shucking his own.

Derek wasn't wearing underwear.

All day, Derek was going commando. Stiles's brain short-circuits. He's pretty sure he makes a noise. He's staring at Derek's crotch, at the thick, uncut erection standing up proudly between Derek's legs.

He wants to put his mouth on it. He wants to touch it. He wants it inside of him. He's not sure which he wants more.

"Like what you see?" The smirk is back. Stiles isn't going to complain. Derek has a right to be cocky.

Heh. Cock.

Stiles licks his lips and looks up into Derek's intense gaze. "Yeah." He shifts his legs wider apart, inviting, giving Derek permission. "I have…" He looks away, face burning, "…things. In my bag."

The bed dips as Derek kneels on the edge, between Stiles's feet. "Things, you say? Maybe you're too young still if you can't even say it."

He knows Derek's teasing but it still gets a rise out of him. "Condoms. Lube. There. Happy?"

Derek crawls up the bed until he's looming over Stiles. "Very," he says, voice nearly a purr. He reaches up, hand sliding under one of the pillows just past where Stiles's head is on the mattress and returning with a bottle of lube. "I've got us covered. Did you want me to use a condom?"

"Not really." Every safe sex lecture Stiles has ever been told goes right out the window. The one and only time Stiles had seen Peter since he'd been resurrected, Peter had leaned over the back of the couch in the loft and stage-whispered to Stiles that werewolves can't carry STDs. So much for impending death from that front. Ever since then he's wondered what it would feel like to have Derek inside of him, no barriers.

"Alright," Derek says. He pops the cap and squirts a generous amount on his fingers.

This is it, Stiles thinks. This is where he loses his virginity. The lube is set aside and Derek's free hand settles on Stiles's hip. He thinks it's to hold him down while Derek preps him, but it's not. Not entirely. Derek's still warming the lube between his fingers as he leans down and takes Stiles's dick in his mouth.

Stiles shouts. There's no dignity about it. All of a sudden there's warm and wet around him and he has to clutch at the covers to keep from coming right on the spot. He's never felt anything like it. Obviously. He's a virgin in all aspects of the word. It feels amazing. Derek's sucking on him and Stiles can't even look. He tries. He looks down and sees Derek's closed eyes and hollowed cheeks and he has to look away.

He moans. He makes a lot of sounds. He's not exactly quiet on a normal day and sex seems to ratchet him up to eleven. He can't keep his mouth shut. Well, he probably could if Derek's dick was in it, but Derek's dick is elsewhere and it's actually his dick in Derek's mouth and oh, god, he's so close to coming. So close. He doesn't want it to end yet.

He probably said that last bit out loud because Derek pulls away with a wet pop. There's a slick finger circling his asshole and when the hell did that get there?

"It's okay," Derek says. He slides up a little and that slick hand trails upward with him, playing with his balls for a mind-blowing instant before closing around his cock. Stiles's whole body jerks, like he's been hit by lightning.

Derek leans on his elbow and lets his free hand play with the short strands of Stiles's hair. "It's okay," he says again, and the way he's looking at Stiles—so incredibly close—is soft and warm. "You can come for me." His hand glides over Stiles's dick like he knows the way, like he's done this before. Stiles shivers and tucks his face against Derek's shoulder. "Come on. You can let go. I'll catch you. I'll always catch you."

Stiles does. He lets go and instead of falling it feels like he's flying. His every nerve is electrified and he feels like he's simultaneously coming apart and pulling back together. Shudders wrack his body and he's gasping into Derek's skin, making quiet noises of pleasure. Derek holds him through it, pulling Stiles's body close and letting Stiles ride it out against Derek's skin.

He relaxes in parts, muscles loosening bit by bit as he falls back against the mattress. Derek's smiling at him, that soft smile that seems to be just for Stiles. "Feel good?"

Stiles smiles back. "Amazing."

"Do you want to-"

"Yes!" Stiles tugs at Derek's arm, making him chuckle as Stiles pulls Derek on top of him. "I want you to fuck me." He blushes after he realizes what just came out of his mouth. "I mean, as long as you still…"

Derek presses a kiss to Stiles's forehead. "Of course." The slick hand slides down again, past Stiles's balls to press against his entrance. Stiles shivers and spreads his legs wider.

The first press inside is strange. It feels invasive and a little painful, but he's not going to let a little pain stop him. He's talked to Danny. He knows it usually hurts a bit the first time, but after he gets used to it it's going to feel so, so good. Stiles wants to feel good. He wants to make Derek feel good. He wants Derek to come inside of him, to link their bodies together in a way that can never be taken back.

Derek kisses him. On the lips first and then down his cheek and his neck. Derek sucks there, in the hollow of this throat and bites lightly. Stiles moans and barely even registers that Derek has one finger inside of him.

It doesn't take long after that. Derek's going slow and taking his time, but Stiles keeps pushing for more. He knows he's probably going to be sore later and he can't even think about walking past his dad while he's all bow-legged, but right now he just wants Derek inside of him. He rolls his hips, pushing back against the one finger inside of him, then two, then more. He's wanton. It starts to feel good fast. He's not sure if that's because the last few months have given him a much higher pain tolerance or just because it's Derek and he trusts Derek and wants Derek.

"Look at you," Derek whispers as he's got four fingers inside of Stiles, rubbing against Stiles's insides and bumping that spot that makes Stiles choke back screams. "So responsive. It's like you were born for this."

"For you," Stiles corrects. "Gonna take you inside me. Make you come."

Derek groans and presses their foreheads together.

"Please, Derek." He hitches his hips up. He doesn't want the fingers anymore. He wants Derek. "Please. Fuck me, Derek. Please."

"Yeah." Derek's fingers pull out and then he's lining up. Stiles moans again as he feels the thick, blunt press of Derek's cock against his hole. He wraps his legs around Derek's hips and nudges him with his feet. Derek rolls his hips, making his cock nudge against him, almost pushing in. "Is this what you want?"

Stiles is not above begging, not when it makes Derek's eyes burn red and his fingers dig into Stiles's hips. "Yes. Please. Fuck me. Please. I need it. I need you."

"You need this?" Derek inches inside.

Stiles cries out. Fuck, that's good. He whines, low in his throat. "Yes," he says, the pressure of his feet against Derek's lower back urging him on. "Yes. Please."

Derek growls. There are definite claws against Stiles's skin but they don't prick him. For all that Derek's feral side seems to have come out at Stiles's urging, he's slow and gentle as he pushes his way into Stiles.

It's so good. Stiles has never felt anything like it. He's so full. He can feel Derek moving inside of him, a glacial push and pull at first that seems at odds with the way Stiles feels hot and frantic. He writhes while Derek stays controlled. He's losing his mind. He needs more. His head rolls back as he arches into one of Derek's thrusts. He's so, so glad Isaac isn't here because the noises he makes are desperate and embarrassing. He's already come once but he can feel a second orgasm rising up on him.

"Derek. Please. Please. I need you. I need you, Derek."

That seems to spur Derek on a little faster. Then Stiles looks up into Derek's Alpha red stare and he's hypnotized. Those red eyes hold him and it's like they become a machine. He thinks Derek is watching Stiles's face for any sign of pain, but pain is long gone and that just gives Derek the go ahead to give him more, then more again.

Stiles takes it. He takes it all. He's greedy. He wants everything Derek will give him and then some. He wants to give equal back to Derek. To make Derek feel as good as Stiles feels. The hardness inside of him reassures him of that. He knows Derek is feeling it. He can see it in the tense lines of Derek's face, feels it in the lines of Derek's back and shoulders as Stiles claws at the skin there. Stiles is practically leaping off the bed and onto Derek's cock and Derek is loving every second of it.

He wants it to last forever. It doesn't. Derek growls and rolls them, pulling Stiles on top of him. The new angle makes Derek's cock shift inside of him and Stiles is in control now. Derek's still pounding up into him but Stiles gets to control the angle and he leans back, hands on Derek's abs for balance as he fucks himself on Derek's hard cock just right so that he's hitting that spot every time.

Derek growls. His claws press in, just enough to make Stiles shiver but not enough to draw blood, and then Derek's head falls back as he comes inside of Stiles. Stiles doesn't stop. He keeps moving, rolling his hips on the still-hard flesh inside of him. His hand reaches down to touch himself but Derek bats him away. Derek takes him in hand and seconds later Stiles is falling apart, back bowed as his forehead comes down to rest against Derek's chest.

His hips take a while to catch up with the situation. He keeps moving reflexively, even after he's already come and Derek goes soft inside of him. Derek lifts Stiles off of him, making Stiles whimper in a strange sort of want and desperation. He doesn't want to stop but his body's done, even if all of it hasn't caught on to the message.

Derek pulls Stiles down next to him. Their bodies slot together like they were two pieces of the same puzzle. Derek kisses him, soft and sweet, while his hands rub along Stiles's back and sides, gentling him into a pool of boneless goo.

He whines when Derek pulls away, which makes Derek chuckle and promise "I'll be right back." True to his word, he is, with a warm damp cloth to wipe the come off of their skin. Derek drops the washcloth on the floor and then pulls the blankets up around him as he crawls back to press kisses into Stiles's skin.

They doze, switching between light kisses and soft touches and sleepy cuddles. They don't turn the lights off though, not yet.

Stiles has plans for round two.