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.
(..) He say she hits em right in the eye, everytime. - Peeta's strong. - What? He can throw a pound sack of flour right in his head. I've seen it. Okay, well I cannot kill anybody by a sack of flour. No, you might have a better chance at winning (..)2012 The Hunger Games