”Are you—am I… hurting you?” Derek realizes he sounds like he’s dying, but Jesus Christ how much restraint can anyone possibly be expected to have when they’ve got Stiles’ pale thighs wrapped around their waist.
“I’m fine. I’m fine. It’s good.” Stiles’ eyes are so wide they could probably roll around in their sockets. His mouth is open in a surprised ‘o’. He wriggles, takes hold of his knees and spreads his legs wider. Derek groans, Stiles’ head flops back in the pillow like he can’t hold it up anymore. Derek sympathizes. His arms feel like noodles and all he wants is to collapse on top of this boy and rut until he comes, but—
“You’re not hard.”
“I know, okay.” Stiles frowns with embarrassment and turns his head aside, cheeks going even redder than they already were. His blush stretches all the way past his nipples, and hmm. Why not.
Derek bends down and takes one in his mouth. Stiles makes a squeaky sound, but whether that’s because of the sucking or the fact that Derek’s dick now slides all the way home, he doesn’t know. He lifts up a bit. Looks down. No, still soft.
“So I am hurting you.”
“No, you’re really not. In fact, hnn.” He makes a bliss-face, eyes rolling back in his head. Derek does the little hip-roll that had been more accidental than anything else, again. Stiles’ eyes fly open and he gasps, open-mouthed. “Oh, God,” he warbles.
“Good?” Derek grins.
“Then why—“ He gives Stiles’ soft dick an offended look.
“It’s a thing. That’s been happening. Since—“ hand-wave “—the thing.”
“Oh.” Derek wiggles closer, pushing Stiles’ knees further apart as he drops to his elbows. Their chests are wet with sweat, even though there hasn’t been much exertion yet. “May I kiss you?”
Stiles huffs a little laugh. “Your penis is in my anus, dude. You can pretty much do whatever you like.”
“What I’d like,” Derek says—he won’t let Stiles derail him—as he rubs his nose along Stiles’, “is to kiss you.”
He starts to push in and out of Stiles, slowly at first, as they kiss. Derek gets a little thrill out of how his stubble must feel on Stiles’ smooth skin. He picks up speed when Stiles begins to make little noises.
Stiles is squirming, like he’s chasing an elusive feeling, maybe. Derek used so much lube it must be dripping down Stiles’ crack. Maybe it tickles. He runs one hand over Stiles’ arm and links their fingers. The other he rubs over the outside of Stiles’ thigh, over the globe of his ass, until he can feel the lube, and then, where they’re joined.
“Mm,” Stiles says in his mouth, “mmm.” Derek opens his eyes but he’s too close to see. Stiles’ eyes are squeezed shut anyway. When he lifts to look at him Stiles clings, arm hooked around Derek’s neck, not letting go. He’s so surprised when Stiles makes a high pitched noise and contracts around his dick that he comes, sudden and hard. He picks up speed to chase the orgasm, kisses Stiles deeper, makes a possibly embarrassing noise.
“Oh wow,” Stiles says, when Derek lets him breathe. “Oh wow. That was… strange.” Derek looks down at the small puddle of come smeared in Stiles’ happy trail. He’s still completely soft.
“I didn’t know… that could even happen,” Derek says.
“How did it…” he glances up, unsure if he can ask, if they can talk about this. “How did it feel?”
“Weird. Not bad weird,” Stiles quickly says, when Derek takes a deep breath. “Just… intense. Like… it was in my belly, more than anything.” He smiles, then. Stiles can be pretty sweet, when he wants to. Derek ignores the hot flutter in his chest. “I liked it,” Stiles admits, like a secret.
Derek wakes up hours later to the middle of the night and Stiles mouthing at his shoulder. Still completely out of it, so God knows what he’s dreaming.
“Stiles,” Derek whispers, but the truth is, he’s loathe to wake him. A sleeping Stiles is rare, still. They’re naked, and smelling of sex, so naturally Derek’s dick perks up as soon as he turns around and looks at Stiles. His pale skin is illuminated in the moonlight beaming through the large loft windows. He lost weight, over the past couple of weeks, but the hollows between his ribs are fading, and so are the black circles under his eyes. The trail on his belly is still flaky with dried come, which should be gross, but is oddly… not. Derek gently touches the hairs, following them down, to where Stiles’ cock lies, soft and dormant. It fascinates him. He should’ve known, really. Stiles used to smell of arousal as much as the next teenager, until suddenly he didn’t anymore.
“What’re you doin’?” Stiles mumbles. His eyes are dark slits, checking where Derek is, then sliding closed again.
“Just looking,” Derek says.
“It’s still just a penis,” Stiles says. He yawns.
Derek puts his head down on Stiles’ hip, rubs his stubble gently across the thin skin. Stiles’ cock doesn’t stir. He shifts forward a little, until Stiles’ pubes tickle his mouth. Stiles smells so good, here. Warm, happy, content. Derek combs his fingers through the coarse curls.
“Go on,” Stiles whispers. “I know what you want to do.”
“You don’t mind?” Derek whispers back.
“Maybe a bit. But if this is… how it’s going to be. I want to… get used to it.”
“Okay,” Derek says. He lifts his head and looks at Stiles, who rubs Derek’s head, messing up the hair.
“You’re always a top?” Stiles asks.
Derek lifts his eyebrows. “No.”
“Then… you don’t mind? That I can’t, uh, fuck you?” Blood pools in his cheeks. Derek grins.
“That’s what dildos are for.”
“Oh God,” Stiles says, voice going wobbly. He drops his hand and his head back into the pillow. Derek noses at his pubic bone, shifts over Stiles so he’s more comfortable, licks at the soft cock laying in its nest of hair. Stiles makes a small noise, but he still doesn’t stiffen.
It’s actually weirdly… nice, to suck on a soft cock. He has to be so gentle, but he likes it, the way it fits completely in his mouth without even the hint of choking him. And Stiles makes lovely noises, he squirms sometimes, says, “Oh God Derek,” a lot, and laughs under his breath like it tickles. Derek can almost fit the head of Stiles' cock and his balls all in his mouth at once.
It comes as just as much of a surprise as the first time, the burst of heat and bitter wetness in his mouth, Stiles gasps wide-eyed as he sits up and grasps Derek’s head. “Sensitive, sensitive,” he pants, and Derek backs off immediately. Stiles kisses him urgently, pushes Derek on his back. “Me now. Me, my turn.”
Derek takes a shuddery breath, lies back and closes his eyes. You don’t have to, he wants to say, but he doesn’t think Stiles wants to hear it. And besides, that fucking mouth. He’s not gonna say no to that kind of enthusiasm.
They get used to it. Derek isn’t bothered anymore when he slides into Stiles from behind and finds a soft cock in his palm. In fact, they learn Stiles can come really hard with Derek’s tongue up his ass. It’s a thing. A fun thing they do a lot especially in the shower, until Stiles is a gibberish mess, not caring his nose is a few inches away from the shower drain after collapsing halfway through again.
“I hate you,” Stiles mumbles when Derek finds his prostate, pushes it with two fingers like it’s a button that makes Stiles go off without fail, every time. Derek takes his mouth off Stiles’ balls.
“No, you don’t.”
“No,” Stiles whispers, letting Derek help him up. “I don’t.”
It’s maybe six months later that Derek wakes up in the middle of the night to the sound of Stiles’ frantic heartbeat. The night terrors have become rare enough that Derek wakes up like he’s been slapped. It’s disorienting and he panics when he doesn’t see Stiles on his usual pillow. Derek is about to push up and roll over when the weight of Stiles registers on his back, and, oh God, the hot, unmistakable prod of a rock-hard erection between his butt cheeks.
“Stiles,” Derek gasps, getting turned on so fast it makes him dizzy.
“Derek,” Stiles moans, broken. He’s sliding his dick between the globes of Derek’s ass like he can’t help himself, pre-come slicking the crack. “Derek, oh please, I can’t…”
Frantically, Derek gropes between the mattress and the headboard for lube and tosses it over his shoulder. “Just do it,” Derek begs, spreading his knees, lifting up his ass. He hears the click of the lube bottle, Stiles’ whimper as he slicks himself up. He’s not going to last five fucking seconds and Derek doesn’t give a damn. “Hurry up,” he snarls, squirming, the head of his uncut dick dragging wetly over the sheets beneath him, his balls swaying heavy. He’s never needed to come this badly in his life. And he does, almost immediately as Stiles slides into him.
“Oh!” Stiles cries out, pushing deeper, wiggling his hips against Derek’s ass, grip iron-tight on Derek's waist. The pressure drives Derek out of his mind.
“Don’t pull out,” Derek warns him. “Just give me—“ He lets the first orgasm subside, and he knows a second won’t be far behind. “Don’t hold back,” he says, when he’s caught his breath. “Fuck me like it’s your only chance.”
“Yes,” Stiles laughs shakily, putting one hand on the back of Derek's neck for leverage, spreading his knees wider for balance. “Oh fuck, yes.”