Stiles is in love with kissing. He could do it all day. He loves the way Derek's stubble scrapes against his chin, loves the way Derek's teeth occasionally nip at his lower lip, loves the way Derek holds him tight while they do it. He's straddling Derek's lap on the dingy old couch someone dragged into the train depot when Erica and Boyd walk in. Isaac is already here, somewhere, off doing his own thing. Stiles tries to pause, out of respect for the other couple in the room, but Derek doesn't let him, dragging him back in with insistent lips and a firm hand cupping Stiles's ass.

Erica lands heavily on an equally dingy armchair. Stiles can feel her eyes on them. "I think you should get in on that."

At first Stiles isn't sure who she's talking to until Boyd asks "Derek?"

Derek pulls away for a second, leaving Stiles hard and gasping for air. He nods. Stiles is confused for a moment until Boyd settles beside them on the couch. Then Boyd is cupping Stiles's face and leaning in. Boyd's lips are rough. They cover Stiles's mouth and coax him into opening up, into letting Boyd's tongue in his mouth. Derek shifts beneath him, his hardness obvious where it pokes into Stiles's leg. Derek grips Stiles's hips hard and grinds up into him, making him moan into Boyd's mouth.

"You should fuck him, right there on the couch," Erica says, her voice floating in from the nebulous space that is anywhere not on the couch.

It's all Stiles can do to focus on the hands on him. Derek's hands slide from Stiles's hips to the button on his jeans, opening Stiles's fly so that he can shove his hands down the back of Stiles's pants, gripping his ass tight in a way that makes Stiles moan. Boyd's hand is in Stiles's hair, holding his head. If he had more hair, Boyd would probably be pulling it.

Derek shoves down Stiles's pants and underwear at the same time as Boyd disengages their kiss to push Stiles's head down. Derek moves Stiles's leg so that he's spread across Derek's ass, Derek's dick hard against his stomach, while Boyd pulls out an impressively thick cock and guides Stiles's mouth to it.

Stiles doesn't have much experience sucking cock. He's only done it twice with Derek, but he's been told he's good at it – eager, shameless – and he takes Boyd in without a second thought. Boyd feels different in his mouth than Derek does, weightier. The taste is different. He closes his mouth around Boyd's cock and sucks, running his tongue along the length of it as he pulls back.

Boyd's hand is still on his head, not really guiding him or forcing him, but holding him steady as he starts to bob up and down.

"Look at that mouth," Erica says. "Like you were born to suck cock."

His ass is exposed for the world to see but he doesn't mind because Derek is kneading the flesh there with one hand, until the hand goes away for a moment and comes back slick. Two fingers push inside of him and he groans around Boyd's cock, causing Boyd to roll his hips up into Stiles's mouth.

His relationship with Derek hasn't lasted long – mostly since the pool incident. It consists of a lot of stolen kisses and Derek fucking him on a threadbare mattress in the back of the depot, but this is new. They've never involved one of the betas before. Stiles doesn't mind. Boyd is hot and Derek seems willing to share. He's a little worried about where everything will go once the fucking starts but he thinks it has to be something like Flappy Bird – once you take the first pipe, it's all smooth sailing.

Derek adds a third finger, then a fourth. Stiles isn't sure if Derek is being extra cautious or if he just likes playing with Stiles's ass. Stiles isn't going to complain. He feels so full. He has Derek's fingers inside of him and Boyd's cock in his mouth, filling him from both ends. The only thing that would be better was if Derek was fucking him.

Apparently Derek has the same idea, because he pulls Stiles up, eliciting a low whine from Stiles as Boyd slips out of his mouth. His legs are moved until he's sitting up again, facing Erica, and he's never not going to get hard when Derek just manhandles him around like he weighs nothing.

Then he's sinking down on Derek's cock and he can't contain himself. His head falls back against Derek's shoulder and he moans, low and loud, as Derek slides into him.

"Wow. You just swallowed him up." Stiles opens his eyes and stares at Erica as she grins at him. "I never realized you were that much of a cock-slut, Stiles."

He's about to respond, almost has the right words in his head, but then Derek grips his hips and lifts him, pulling him almost all the way off his cock before bucking up into him. Stiles gasps, words forgotten and lets his head fall back on Derek's shoulder. He reaches a hand towards his own neglected cock, but Boyd stops him.

With a small grin, Boyd slides off the couch to knee between Derek and Stiles's spread legs. He leans down and takes Stiles in his mouth, returning the favor from earlier and making Stiles shout with surprised pleasure. No one's ever sucked him before and it feels good. It feels amazing when combined with Derek inside of him and he can barely think, barely focus on anything that's not the dick inside of him or the mouth around him.

"Derek." He turns his head to the side, gasps a warning. His hands clench in the fabric of the couch and he tries to hold on, but it's hard. "Boyd. I'm gonna... I'm... I..."

Boyd doesn't stop sucking. If anything, he works harder, pulling at Stiles with his tongue. Derek fucks into him hard – not as brutal as when he has Stiles bent over in bed, but close. It's more than Stiles can handle and he comes with a strangled shout. Derek thrusts up into him a few more times and then he's coming too, spilling inside of Stiles and leaving a mess on Stiles's thighs.

Derek pulls out, but instead of tucking them both away, he holds Stiles's legs up, opening him wide for Boyd. Boyd straightens, puts one knee on the couch between Derek's legs and then he's pulling Stiles's hips forward and up, lining him up so that Boyd's thick member can slide right in.

It's so easy this time. Stiles is already slick with come. He barely feels the difference in Boyd's girth but he feels everything else. He's supersensitive, his body on fire post-orgasm, so he feels every inch of Boyd as he slides in, slow at first and then faster until he's fucking Stiles like a truck, pounding forward hard and fast and relentless. All Stiles can do is gasp and moan and enjoy the ride.

"You like that, don't you, Stiles? Isn't my baby good at fucking?"

"Yes," Stiles gasps out, responding to Erica for the first time. Derek chuckles behind him and pulls at Stiles's legs, forcing him open wider.

Then Boyd lands a hit just right, ramming into Stiles's prostate and he screams with pleasure.

"Please." Stiles's voice comes out wrecked. "Please." He's not sure what he's begging for, but he knows he needs... something. Needs it with his entire being. He's being fucked into next Tuesday, fucked so hard it hurts, and all he can feel is that need building inside of him.

Boyd stiffens and comes, making Stiles feel extra wet, but he's too far gone in need to care. He whimpers when Boyd pulls out. He feels bereft, lonely.

"Aww. Poor boy isn't done yet. Whatever are you going to do with him?"

"I've got him," Derek say, and then he's turning, pushing Stiles face first down on the couch. Stiles spreads his legs, hoping, and his hope is rewarded as Derek slides into him once more. His face is turned towards Erica and he watches as she rubs her clothed crotch in time to Derek's pounding thrusts.

Erica's eyes meet and hold onto his as Derek fucks into him, pushing Stiles closer and closer to second orgasm. He can't look away, can't move, can't do anything but stare and pant and writhe as Derek moves inside of him. It's so good. It feels perfect and right and the best, and then it's over far too soon.

His eyes squeeze shut as he orgasms, coming untouched, seed spilling onto the already messed up fabric of the couch.

When Derek pulls away it feels like a loss, but Stiles has no words left to complain. He's fucked out and sore in all the right ways. It's exactly what he needed and way better than he expected.

That was way better than Flappy Bird.