- (idiomatic) To have sex
- I can see the sparks between us, let's get it on, baby!
- (idiomatic) To hurry up; to get a move on.
- I need to get it on, there's not much time left.
- (idiomatic) To invite an opponent to a fight, or to agree to a fight.
- You want a piece of me? OK, let's get it on!.