Stiles sort of assumes that Derek doesn’t do the whole ‘public’ thing. He’s never been much on public displays of affection with anyone, not even in a friends kind of way, so he doesn’t see why this new thing between them should change anything. Furthermore, Stiles doesn’t even know what this ‘thing’ between them is. Because Derek kissed him once when he’d saved Derek’s life and gotten hurt in the process. And ever since, Derek has this habit of sneaking into his room, or cornering him into a hallway (or anywhere really) and sneaking a few kisses here and there.
They’ve never actually talked about it. Mainly because Stiles is scared that if he brings it up, it’ll break whatever spell has its hold on Derek and they’ll never get to kiss again. And Stiles doesn’t want to risk that. Because dammit, he wants Derek to keep kissing him. A lot.
So whenever they’re around the others, Stiles tries to act normal. He still teases Derek, still snaps at him sometimes, still acts like he doesn’t want to just cross the room and capture those lips in a searing kiss. Even though he’s sure Derek notices his eyes on him, pretty much all the time. And every once and again, Derek will look back, eyes lingering just a second too long. And Stiles knows that Derek is thinking the same thing he is.
Of course Stiles has to go and fuck it up at some point, when Isaac brings up the prom and Scott suggests that Stiles ask that girl from their economics class that has a thing for him.
“She doesn’t have a thing,” Stiles says, brushing it off, and he refuses to look at Derek. Instead he busies himself in the books that are stacked on the table.
“She totally does, bro,” Scott says, nonchalantly. “You should ask her. I know you don’t want to go alone, and it’s not like you’re seeing anyone, right?”
Stiles sucks his bottom lip between his teeth, looks up to find Derek eyeing him intently. But Derek doesn’t say a word, and Scott is looking at him expectantly, so Stiles shakes his head and forces a smile. “No man, of course I’m not. Single as ever, that’s me.”
“Good,” Scott says, “So ask her, and maybe you won’t be single for long.”
“Right,” Stiles says, humoring his friend.
And then Derek gets up without saying a word and stomps off into the kitchen. And Stiles’ stomach feels like a brick.
Stiles has to give Scott and Isaac a ride home, so it’s not like he can stay behind and try to have a word with Derek, who’s clearly still in a bad mood by the time they leave.
Stiles tries to just ignore it, but it’s a nagging feeling that simply won’t go away, and when he’s still worrying about it in the evening, he finally picks up his phone and calls Derek, who… doesn’t pick up.
“Derek,” Stiles says after the beep, “Okay, I have no idea why you’re being an ass right now and ignoring me, but it really sucks, okay? It was Scott that brought the whole thing up anyway, and I even looked at you, man, and you gave me absolutely nothing. I never asked anything of you! I never wanted to mess up whatever it was that was going on. I never told anyone because I know how you’re all secretive and you’d probably rip my throat out when someone found out about… about… whatever it is we’re doing, alright? And now you’re obviously pissed and I have no idea why, and I didn’t even do anything wrong, okay? What, am I supposed to go to the prom alone? Which I am, by the way! Because I have no intention of actually asking this girl that I’ve never even spoken two words to! Because of course I’d rather go with you, but I know that’s never gonna happen, not even if hell freezes over, and… Fuck. You suck, man.”
Stiles hangs up the phone, throws it on his bed, and buries his head in his hands, because damn… He was not supposed to say all that. He turns off his phone in a panic, and tries not to think of how he’ll ever face Derek again.
He takes a shower before bed, and when he arrives back into his bedroom – hair still wet and sticking out in all directions – he nearly stumbles back into the door when he sees Derek leaning against his windowsill.
“Jesus Christ, are you trying to kill me?” Stiles asks, perplexed, and somewhat glad he put on his sleeping clothes in the bathroom.
“You turned off your phone,” Derek says, as if that’s any kind of explanation as to why he’s here in Stiles’ bedroom at eleven in the evening.
“Yeah, because I clearly should never be allowed to use a phone ever again,” Stiles sighs, looking at the object in question with a murderous stare.
“You realize you never asked me, right?” Derek says, not moving from his spot by the window.
“What?” Stiles frowns.
“To the prom,” Derek clarifies, “Or anything else, really? You’re mad at me for not accepting to go to the prom with you, but you never actually asked me.”
“Because you- !” Stiles starts, stopping himself in utter confusion.
Derek takes a few steps forward, until he’s right in Stiles’ face, staring him down. And Stiles is actually afraid that his heart might jump out of his chest.
“Ask me…” Derek whispers, his eyes fixed on Stiles.
“I…” Stiles starts, swallowing hard. And he tries to get the words out, he really does, but then he’s pressing his lips against Derek’s and he doesn’t even know how it happened.
But Derek kisses him back, slides his hands down Stiles’ back, until they’re gripping him tight around the waist and pulling him in. Stiles’ tongue pushes past the brim of Derek’s lips hungrily, searching out for Derek’s. They kiss until they stumble onto the bed together, Derek slotting his body perfectly over Stiles’, until they’re both breathless and satisfied.
When Scott brings up the girl from class the next day, Stiles simply smirks and says he’s not going to ask her out.
“Why not?” Scott frowns.
“He already has a date for prom,” Derek says as he comes to stand next to Stiles, slipping his fingers down to tangle with Stiles’. Stiles holds his breath as he looks at Scott expectantly, squeezing his hand tightly around Derek’s.
Isaac quirks an eyebrow at them, but he’s smiling. Allison and Lydia seem to be having an entire conversation simply by looking at each other. And Scott smirks as he looks down at their joined hands, and sighs, “Finally.”