What is a flirt punch and how do you know when someone does that?

A girl in my school punched me in the arm, not like full on force like I want to kill you punch. Just a random punch from her.|||A flirt punch is more of a push with a fist. It is usually after a but of flirting and when the guy says something that's a bit of a neg. If there was any real force to it, it wasn't a flirt punch