"I told you not to go out alone," Derek shot back. "You disobeyed. That's a 'big deal', Stiles!"
He was sure now that Stiles never meant for him to find out that he'd gone out. Was this a regular thing? He'd thought Saturday night had been the first, but perhaps Stiles had been sneaking around since he got here. If he showered as soon as he got back, there was no way for Derek to know who with.