Context: I was at a bar with my girlfriend and some friends and saw a dude trying to hit on my girlfriend and buy her a drink while she was closing her tab. I choose to ignore it as she was handling it well, and when she returned to my side she hugged me and the guy who was trying to flirt followed her, approached me and grabbed my bicep. I asked him why he was grabbing my arm and told him to let go, while showing slight resistance. It was loud in there but I could tell he verbally responded aggressively and didn’t release me. Before I was about to punch him with my free arm, I heard my girlfriend say we should go, to which I was able to get my arm back and we walked away, while this guy chirped at us. At what point would it of been the appropriate to hit this guy?