1
general::
Phrase(s): sleep around (with someone)
Inf. to have sex with several partners over time; to be promiscuous. • They say she sleeps around with just anybody all the time. • Yes, she sleeps around.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Engage in sex promiscuously, as in Fortunately, no one mentioned that both of them had slept around in their younger days. [Colloquial; 1920s]
American Heritage Idioms