A/N: Just a quick Sterek fic, written in response to a post from tumblr user crossroadswrite. As an experienced theater nerd with lots of costume changes throughout the years, I know that there is nothing more satisfying than a well-executed quick change. Even if it's in an awkward place with people gawking at you, lol.

It took some juggling for Derek to get his phone out of his pocket when he had a backpack slung over his shoulder, two textbooks in the crook of one arm, and a basketball tucked under the other, but he managed it without dropping anything. He would've waited until he could drop his stuff in the backseat of his car before checking the new text message, but the only people who ever texted him were his friends and he was pretty sure that all of them were supposed to be occupied right now.

It was Erica. [need ride, come 2 aud]

Erica was supposed to be helping with the school play, working backstage and helping with hair and makeup and costumes. It was a musical, Derek knew that much but not much else. Something about gamblers and strippers, honestly he hadn't been paying much attention all the times she had rambled about the long rehearsals.

The only time he had tuned in had been when she had mentioned Stiles, but that was not because Derek had a crush on Stiles. It was just because Stiles was on the lacrosse team and had always been a sports guy even before he'd made the cut, so this musical thing was a big departure from the norm where he was concerned. It was like High School Musical level stuff, how could Derek not be at least a little bit intrigued by that? Maybe Erica had a crush on Stiles; she certainly talked about him enough.

Maybe the rehearsal had let out early. It was supposed to be a dress run instead of one of those run-one-scene-over-and-over things, so Derek didn't really know how long they could be expected to last. He wrestled his phone back into his pocket and changed direction, heading through the empty hallways toward the auditorium.

The closer he got the more suspicious he became, mostly because he was pretty sure he could hear singing and that meant the rehearsal was far from over. Which meant that Erica was luring him there for some probably-nefarious reason. Really, he should know better than to trust her by now. But he was already halfway there and he might as well give her a piece of his mind in person.

Derek rounded the last corner before the door that lead out onto the auditorium stage and promptly collided with a trashcan, flailing in a very undignified manner as he struggled between staying upright and not losing sight of what was in front of him.

He wasn't quite sure what he was seeing at first, but he was sure there was more bare skin than there should be. Also, considering the smattering of moles on the broad expanse of bare skin in front of him, he was pretty sure he knew whose bare skin it was.

He wasn't sure whether to strangle Erica or buy her a fruit basket.

Erica was there, off to the side and with what looked to be a pair of pants draped over her arm. She had a fedora perched precariously on her head and an untied tie around her neck, and she was holding out a suit jacket in front of her, ready to help Stiles into it. For his part, Stiles was currently in his boxers in the middle of the hallway, just shrugging a button-up shirt over his broad shoulders.

As Derek watched, Stiles started hopping on one foot and trying to kick off the pants that were hooked around his ankles, a difficult endeavor with his dress shoes still on. He looked utterly ridiculous and by all rights Derek should be laughing, and yet he was gripping the edge of the trashcan and trying not to swallow his tongue.

"Why did I let them convince me to do a costume change here?" Stiles was grumbling. He reached for the suit jacket, letting Erica pull it up and straighten it while he went back to buttoning.

"Because you wanna look to look extra-snazzy when you rock the boat," Erica said, shaking out the pants on her arm and holding them out just as Stiles managed to free himself from the last pair. He took hold of her shoulder with one hand and stepped into them, letting Erica literally put his pants on him while he snatched the tie off her shoulders and looped it around his own neck, fingers quick and agile.

Derek didn't know how Erica could function with her face that close to Stiles' crotch - she was literally stuffing her hands down his pants, tucking his shirt in for him and somehow miraculously not groping him - but then Erica had never been one to freeze up in front of people she liked, like Derek. Wait fuck, people he liked. Derek considered climbing into the trash can and closing the lid before Erica could realize her little scheme had worked because that would be less humiliating than accepting the years' worth of taunting that would follow this moment.

He did not do that. Instead he stayed exactly where he was and marveled at how well the suit pants fit once they were properly fastened and how fantastic they made Stiles' ass look. Then Erica was buttoning the jacket and Stiles was plucking the hat from Erica's head to put it on his own. The entire ordeal couldn't have lasted more than a minute and a half, and yet here Stiles was, suddenly looking ridiculously good in a sleek pinstriped suit with a red flower in the lapel, no evidence at all of what a rushed mess the process had been.

"We good?" Stiles asked, and he did a turn to let Erica look him over. Only that left him facing down the hallway. Where Derek was still standing, like a voyeuristic moron. Stiles' eyes widened when he caught sight of him. "Derek," he said, sounding a little strangled. He cleared his throat, reaching up to loosen the tie he had just tied.

Erica slapped his hand away and said, "Don't touch, it's perfect!" She sent Derek a positively wicked smirk that made him flush even more than the fact that Stiles was still looking at him with his mouth hanging open and began dragging Stiles toward the door. "Come on, Nicely, you've got sinners to save," she said and shoved him through.

Stiles tripped through the door, spinning around to send one more look back at Derek as he straightened his hat. Then music blared from onstage. His head whipped around toward it and he took off running, leaving Derek to gape after him even once the door had drifted shut.

Erica leaned against it, arms crossed over her chest and a wholly self-satisfied expression on her face.

"You're welcome," she said.

Derek reconsidered getting in the trashcan. The only thing that stopped him was Erica striding forward and holding out a scrap of paper torn out of a notebook. It had a phone number on it. He raised an eyebrow at her, since the speech part of his brain hadn't quite rebooted yet.

"Stiles thinks you're cute," she said simply. "Bring him flowers on opening night and I guarantee you'll have a date for prom."

Erica was totally getting a fruit basket.