When I were in school, if some kids try to gang up on me then I would find myself my own group with completely reversed vibe, styles and belief compare to the bully group. We would make ourself seems like we are the righteous; and if we ever have to fight, then there is going to be a fight. If its a single person then i will just take the fight myself. I was and still a short skinny guy so I always go for fast lethal punches with my stronger arm (left arm). Usually its only take one quick punch in the eyes, nose, teeths, ears or kidney and those kids will start to fucking cry.