She has a reputation for being 'good/great in the sack'. [=for being a good sexual partner]
He's ready to 'jump/climb in the sack' [=have sex] with any woman who'll have him.
The company 'gave him the sack' [=fired him] for improper conduct.
(..) than Paolo ever was. You care about me, you're loving, you make me laugh. If I make you laugh, here's an idea. Invite Paolo to have a romp in the sack... ...and I'll stand in the corner and tell knock-knock jokes! What we have is special! All Paolo and I ever had was... "Animal sex"? (..)1996 TvShow: Friends Title: The One Where Dr. Ramoray Dies Season: 2 Episode 18