Stiles laughs, and it lasts for a pretty long time because wow no Allison, do you not remember how the last dance party went where someone was 'persuaded' to go with Stiles? It did not end well. But also because between Allison and Lydia they could absolutely get him a date, no question. Even apart the two were terrifying but together?

Nothing they couldn't do.

"That sounds equally terrifying and reassuring. Well done." And he's holding a hand up for her to high five, better not leave him hanging for long, girl.