Max just hummed as Primrose insisted she wasn't drunk. He believed her, even if many people might not. He didn't see a good enough reason for her to lie about that to him.
A short silence ensued, one where Max wasn't one hundred percent sure what to do or say. He didn't want to move - which was always something new when it came to the boy - but he also didn't want this to be awkward.
So, throwing the two together, the Gryffindor opened his mouth (before thinking) and said. "Can we just sleep together, here, tonight?" Not quite realising that the start of that sentence could have had very different connotations than that of what he'd actually meant. Of course, Prim could say no to that, Max wouldn't mind if she'd prefer to go up to bed.
Max just... didn't see why they had to, if they were both comfortable.