Ruin their life? I think you're the idiot here. Seriously kid, just hit him, none of these moves people have been telling you to do, like the nose thing, because as someone already said, if you do it right it can kill. Just walk upto him/wait until he takes the p*ss out of you again and crack him right in the mouth or headbutt him. If you fight back it'll stop. If you're gonna headbutt him, tense your head and neck muscles, lean your whole body back and swing yourself forward, making sure you land him on the nose - He'll go down.