Chapter Text
They hadn't done the proper amount of research, is the thing. They'd all looked into how werewolf pregnancy worked, sure, but they failed to realize that if the alpha didn't have a cub of his own before the pack started reproducing, well…turns out alpha ruts are a thing. A thing they didn't know about but should have. Stiles blames himself. And also Peter for taking away the alpha they should've had. The one who knew these things.
Derek had tried to help, at the beginning, when his instincts first started going haywire. He'd been lucid for good stretches, had helped research. He was the one who found the solution, but he'd rejected it. Said there must be another way. Unfortunately, his lucid days were gone now. He was currently chained up and caged in the basement because his instincts had finally overridden his humanity. Stiles had gotten an agreement out of him before that, at least, but they were still sitting here. Discussing.
“Enough. It's the only answer we've been able to find and it's the one we have to go with.” His voice is sharp enough to make the others finally shut up and listen. He can see that they want to argue, to keep searching, but they've already let it go on too long, Derek will be lost to them if they wait any more. “I'll go first.”
“Stiles, you can't -” Scott tries to grab his shoulder but Stiles shrugs out of his grip.
“You volunteering? Yeah, didn't think so.” He moves towards the basement door, grabbing the bag of supplies he'd bought when he realized there wasn't another choice. The plastic bag rustles as he moves but before he can get very far, it's being yanked out of his hands. “What the fuck? Peter, give it back.”
“No. Scott's right. You can't be the first.” He holds the bag out of Stiles’ reach when he tries to snatch it back. “He's too feral. He'll hurt you without meaning to. It has to be one of us first, a werewolf.” Stiles searches his face but doesn't find any deception, then turns to scan the faces of the others. Scott won't meet his gaze and Isaac is flushed, looking terrified.
“I'm not really seeing an option for that here. So I'll take my chances.” He tries for the bag again, but Peter's too fast for him.
“I'll go.”
“You? Yeah, I don't think so. You killed Laura. I won't give you a chance to kill Derek too. You think I'd trust you alone with him?”
“Of course not. I fully expect you to watch.” Peter's smirk is just this side of dirty and Stiles startles, because he hadn't been expecting that. At all. He'd thought Peter was bluffing about actually being willing to do this, had thought it was a ploy, using their desperation against them to take Derek out. He's so shocked he doesn't even realize Peter's turned back to the others until he speaks again.
“Chris, I'm sure you've got a gun with wolfsbane bullets. Pass it over to Stiles, insurance for him.” Everyone looks as shocked as Stiles feels, and he takes the proffered gun on autopilot. Peter opens the door to the basement and the sounds of a feral alpha come flooding back up the stairs, snarls and growls and low keening noises. He's still rebooting as he follows behind, closing the door after them. Despite the noises Derek is making, the rustling of the bag as it's set to the side seem loud.
“I appreciate your foresight, going to the store. Wholly unnecessary for me - like you, I expected we'd have to do this sooner or later.” Peter's stripping just out of reach from the cage, and it's easier to watch him than to look at Derek - half shifted, naked, faint lines of red all across his skin from where he'd been clawing at himself. The chains seem to be holding up, when Stiles does flick a glance at them, the bars to the cage undamaged. “Break the ash Stiles. I can't get in otherwise.”
Stiles refocuses on Peter, unable to stop the blush on his cheeks when he finds the man standing there unashamed, naked and hard. Stiles steps just close enough to smudge the toe of his shoe through the line, flinching back when Derek roars.
“Excellent. Now then, you might want to take the safety off of the gun, just in case.” Peter winks before turning to face the cage, stepping closer to it. When he's still just far enough out of reach, he bends forward a little and Stiles sees a flash of black between his cheeks. Then the man is reaching between them, wiggling the plastic and popping it free with a wet squelch. He drops it to the floor, uncaring, and unlatches the cage door.
Derek, for his part, has gone mostly silent, nose twitching as he scents the air. Stiles chances a better glance and finds Derek's cock is hard, swinging as he starts to pace along the back wall, eyes fixed on Peter. Stiles raises the gun, just in case. There's a breathless moment when Peter finally opens the door and steps inside, and then everything is happening at once. Derek snarls and charges, Peter snarls back, falls into the beta shift, and there's a blur of motion, Stiles trying to track it with the gun and failing. He thinks Peter has tricked him after all when suddenly there's a high pitched whine and they slow down.
Peter is pinned to the floor on his belly, Derek's teeth sunk into the side of his neck. It's not a killing move though, not if the way Peter is laughing is any indication. He can see Derek's hips shifting, hear the keening he's starting to emit, and watches, enthralled, as Peter heaves himself upwards until his ass is in the air, shoulders pressing into the concrete.
“Just hang on nephew, I've got you.” Peter reaches behind himself, spreads his cheeks, and Derek rumbles out his approval to the sound of Peter's gasp as his rutting finally pays off, his cock sliding home inside of his uncle in one strong thrust. “Fuck! Yes, just there. Yes Derek.”
It's hard and fast after that, Derek's teeth never leaving Peter's neck as he rabbits his hips, fucking him hard. There's a trickle of blood sliding down Peter's clavicle and Stiles spares a moment to be grateful Peter stepped in. He's right, even with prep, Stiles’ body couldn't have taken the frantic pounding. It goes on for an eternity and for a second. Sometime during, Stiles’ arm drops, thumb flicking the safety back on. He tries to focus on the brutality of it, tries to will away the tingle of arousal in his gut. He shouldn't find this hot. He shouldn't, but he does, on some deep dark level. There's no mistaking that Peter is enjoying it, not with the way he's moaning, his elbow rocking as he jacks himself off. Derek's hips don't stutter to a halt until there's the unmistakable splatter of Peter's come painting the floor beneath him.
Stiles can't help the burn beginning in his belly, but he does his best to ignore it, especially when Peter looks up and meets his gaze. The man smirks as he slides himself forward when Derek releases his hips. There's a growl rumbling steadily from Derek's throat and a quick glance down shows his cock is still hard and angry, balls swaying slightly still, full and round.
“Well, I gave it my best. Seems I'm not enough to sate the hunger.” Peter's brow quirks up, smug expression on his face as he rises. He takes a half step towards Stiles, but changes course when Derek's growl gets deeper, keeping to tell other side of the basement as he moves to gather his clothes. He shifts to the side when he reaches the stairs, making room for Isaac before slipping past him and moving upwards, voice echoing back down the stairwell. “Stiles has brought lube, if you need it.”