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"Well, obviously, this wasn't what the spell was supposed to do."
Derek widened his eyes at-- Lydia. That was Lydia. "Obviously."
Stiles' face scoffed and rolled its eyes back at him before-- That had to be a force of habit, because Derek was fairly certain Lydia had just tried to flick Stiles' hair over his shoulder. Which just. No.
"Even if we can't reverse it," Stiles cut in, his normal grin trying to stretch out across Lydia's face, "it should wear off in a few hours. So chill."
Lydia pursed Stiles' lips and that just...so wrong. "I don't like you using my voice like that. Stop it."
"Sure," Stiles waved Lydia's hand at his face (which was on her, and damn he hated this) and went back to studying the book they'd been using. Or the translation notes, anyway. "Just as soon as you stop doing that--lip thing with my mouth and bitching everybody out with my voice."
Lydia glared a moment before grabbing the purse up from between them and attacking Stiles' Lydia-face with a--glossy lip balm. "And stop chewing my lips, I swear to God, Stiles."
It looked like an afterthought, maybe even instinctive, for Lydia to apply the balm to her own lips after that. Which were Stiles' lips. They were tempting enough on their own, but the way Lydia kept them pulled into a pout made them borderline obscene.
The gloss pushed that past borderline. Derek dropped into Stiles' computer chair and dug his claws into the underside of the seat. If he was lucky, Stiles wouldn't notice for a few weeks.
Satisfied that both of their mouths were shiny and ridiculous, Lydia popped the gloss back into the recesses of her bag and leaned over Stiles' shoulder. They didn't talk, eyes flicking back and forth over the page and Lydia frequently returning to the actual book itself to check the translation against the original.
Aside from the pale pink sheen to Stiles' mouth and the wrongness of their expressions, it was almost normal. For five minutes.
"I can't remember what line I was working on," Lydia declared, snapping the book closed. "I have your brain and it's broken. Why isn't it--"
"It probably needs my evening dose of adderall," Stiles sighed, reaching Lydia's hand into his own back pocket for his phone. Lydia's expression was much calmer shock than Derek normally got to see on Stiles' face. It was kind of funny. "Yeah. It's a little early, but you can go ahead and take it now. It'll take a bit to kick in, but..."
Lydia's shoulders shrugged at her as Stiles hauled her body across the bed and out of the room.
Barefoot, as they'd apparently learned an important lesson before Derek had shown up.
"What were you trying to do?" Derek asked, as Lydia flopped over into the warm spot Stiles had left.
"It was supposed to be an illusion," Stiles' voice responded, but without the gestures that normally accompanied it. "Taking the appearance of another. Which, arguably." She gestured down at Stiles' body, but--
The hand hitched and hesitated, paused while Lydia shifted on the bed again, wiggling her--
Derek narrowed his eyes. "Stop it."
"W-o-w," Lydia drew the word out, almost breathy and still in Stiles' voice and fuck. "I would not have expected..." She sat up, unashamedly eyeing Stiles' crotch from her new perspective of attached-to-it. "I might be impressed."
"Lydia."
"I think I need to visit the washroom," she decided, standing abruptly and walking determinedly toward the door. "He's had my body in there long enough to be suspicious anyw--"
A lot of things happened at once.
He had Lydia pinned to the door by Stiles' shirt and was growling at her smirk.
But also.
He felt--off. Like the world and his brain were moving in opposite directions.
And.
He was staring at his own face.
Derek blinked. The growling had stopped abruptly, and his own face was blinking back at him. Fuck.
"Hey," Lydia's voice came through the door. "I have Stiles' pill, and by the way? He was definitely looking down my shirt, so it's only fair I get to see what's in his pants."
Derek watched his own eyes bulging, his mouth dropping open and he was blushing. Or. Stiles was blushing, apparently. With Derek's face.
"Uh--"
"No, Lydia," he snarled. It--didn't sound right, in Stiles' voice. It also felt very, very weird, with the lip gloss.
There was a pause, then a cheerful, "I take it the spell didn't wear off, then?" from Lydia.
"Looks like not," Stiles said, and...he still hadn't let go of. Well. Himself. He was staring down at Derek's hands where they were clenched in his shirt, though. "So. Uh. Lydia--was going to scope out the goods?" he asked incredulously, waiting for Derek's nod before continuing. "And you--didn't like that?"
"She should respect your privacy," Derek grit out, trying not to blush himself. It was harder, in someone else's body. "You should have too."
On the other side of the door, Lydia sighed explosively. "Are you two done flirting yet? I need my shoes if I'm going to be sexiled."
Derek groaned and let Stiles' head fall back against the door.
"Are we flirting?" Stiles asked, still holding him against the door. "I mean. I'm just saying. I wouldn't, y'know. Mind. If we were?"
He thunked Stiles' head against the door once more for good measure and winced when the pain didn't just flash and disappear. "...later," he huffed, trying not to watch his eyes going wide and-- When was the last time he'd smiled like that? Too long.
Figures it took a body swap.