You don't need to LD to learn how to fight Just clench your fists, find some courage, and just start swinging at your opponent.

What you want to do, I am guessing, is LD to find the courage to actually do something. In real life, you know you really want to kill that jackass, and you play a scene in your head where you are tombstoning that mother f****r into the cement and start beating the crap out of him. While you know you are capable of beating him up, you just can't bring yourself to swing your arm and break his face in real life.

If you want to hit someone/beat them up, do it in your dream. Bring that person you dislike, and just begin hitting them in the face. This'll prepare you for hitting them in real life. If you want to practice fighting (like a fist fight, or karate), that is another story, as the physics in your dream is entirely different and you might be fighting like in the matrix. Sometimes, when I know I can't just hit someone in real life, I do it in a dream. It's fun, and it's definitely tempted me and gave me more courage to actually do so in real life.