It's like Papyrus is drunk, except not exactly. Except vanishing and coming back drunk isn't something Sans can imagine Papyrus doing. Sans didn't know that particular kind of hysterical laughter was a trait the two of them shared, either. Where has Papyrus been? The question is even more important and Sans still doesn't want to ask it out on Papyrus's front lawn.

"Why d'you think I take all those naps?" Sans says, forcing his mouth to form that casual grin he's supposed to be making here. "Can you stand up?"