get it on with someone—(U.S. sl.) have sex with a person (also: get it off with someone): And it wasn’t only with Prunella:
- He had wanted to get it on with Evelyn—Evelyn the Untouchable, for Christ’s sake!
get on with someone—maintain a friendly relationship with smb.; be on good terms with a person:
- I didn’t get on well with my parents at all at this stage—they had messed up one of my best friendships.