Tell me this doesn’t look like an AU in which Derek and Stiles were fooling around and Stiles is trying to sneak Derek out before the Sheriff gets home, but he catches them right as he comes in the door. And Stiles tries to play it off that they’re just friends and Derek was there studying. But Derek is being a little shit and trying his hardest to get Stiles flustered and caught up in his own lie.
"Well, Derek. You want to stay for dinner?" the Sheriff asks.
"Oh yeah!" Derek answer with way too much enthusiasm.
"Fantastic," Stiles mumbles, thinking his life is now over.