It sounds like a proposition, but he's honestly heard so many of them tonight that maybe he misheard. Maybe he's just assuming. Sometimes it's easier to assume and have an awkward misunderstanding than to be caught off guard. He isn't sure what would be easier with Jyn. But why not? Why wouldn't she? Everyone else does.

He simply does not acknowledge it at first.

"I need another drink. Since you have stolen mine." Maybe they can go somewhere and drink. Maybe that's what she meant.