NTA People like to play these stupid games for some reason. When I was in school kids played the "game" were they would come up behind you and tap your nuts, not hard enough to really hurt, but annoying all the same. Not sure if that was a game boys played everywhere. I told everyone from the beginning I'm not playing and yet one of my asshole friends still felt the need to tap my nuts anyway. Not that I'm advocating violence, but a punch to the face did get my point across. So your friend should be glad you didn't haul off and slap him back. Blocking him definitely seems to me like a better way to handle it than what I did, especially considering you asked him to stop multiple times.