What does it mean to jump someone?

I was talking to the guy I'm dating, the usual hi how are you... Then he asks if I've ever wanted to jump someone. I assumed he was asking if I've ever wanted to fight someone, so i asked if he was in this situation in which he laughed and said ' I don't have any energy left after the gym, it wasn't that kind of jump I meant'. I'm now thinking it's in relation to sex? This question just randomly came out of nowhere.
What does it mean to jump someone?
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