When somebody is trying to bully you and it becomes apparent that they are likely to attack you, the tactics you use at that “pre-fight” stage can put you into a position of enormous advantage without the aggressor realising what you are doing. You can line yourself up to strike them decisively on a vulnerable point without them having any idea of what you are preparing to do.
The video below demonstrates how to line them up and discusses the legal implications of such an action.