Don't mess with Snape

"So Severus, how was it?" asked Dumbledore.

"Go what?"

"You just went to see a doctor, I believe".

"Oh that. Well, he told me to take it easy for the rest of the year or I won't be able to walk next year"

"What? Are you going to need an operation?"

"No, Albus, he said be carefull with your hip"

"Aww, is poor Snivellus going to have a hip replacement for too many hours studying ?"

"Not really Black. He told me that if I keep on having this much sex my already weakened hip bone was going to crack."