Right... Yeah, we're all a bunch of drunks. Surprised we ever catch anyone!

[He keeps the forced smile on his face, but he couldn't exactly accept the offer, even if he had some kind of power that would allow him to find a bottle of whiskey hidden somewhere on this huge campus.]

All right, you're on. I'll take you up on that.

[Since he has absolutely no intention of looking for it, then he doesn't have to reveal that he's forbidden from drinking, like he's some kid.]

Fortunately for me, I've got no class.

[Okay that pun was pretty bad, but he's proud of himself for managing an English pun nonetheless. Progress!]