"Professor Dumbledore," Hermione asked, scuffing her foot shyly against the carpet.
"Do you want to do something completely inappropriate that neither of us would ever approve of/agree to?"
"Certainly. My office or the Room of Requirement?"
"The Room of Requirement would be better, after all, you've got that thing for bondage gear and we won't need to waste magic summoning up supplies."
"You really are the brightest student in your year, aren't you?"
I highly recommend reading the rest of them--the last one especially is brilliant.