hop in the sack
Meanings of "hop in the sack"
In a general sense, it means to get into bed. But it's usually said with a sexual connotation, meaning to have sex with.
Can also be phrased as jump in the sack, climb into the sack, get in the sack, etc.
to get/climb/jump into the sack (with someone) - to have sex, usually with someone that you do not know very well
заниматься сексом с кем-л., часто: с не очень хорошо знакомым партнером.