The Butt Swatting Game

I had this dream that some people were playing this game involving swatting each other on the butt. But there were special rules and things you had to do before swatting someone. So this kid swatted me on the butt and since I didn't know the rules, I swatted him back. But then he said "you can't swat me back yet, you have to follow the rules!!" So I said "sorry, what are the rules?? I don't know the rules!!" And that's all I remember.