If you believe that someone whom you are beating could improve in any way through this, you should follow the same rule. After a mistake, go to someone who is stronger than you and ask him to beat you a bit so that you can better yourself!
Gyan Yogis say that there is no duality. Everything is one and everyone is the same because god is in everybody. So if God is in you, in me and in everyone around, against whom do you want to direct your aggression? Anger can only exist in duality. When everything is God, then everything is the same, everyone is love.
You have to accept your anger. It is a natural feeling, created by god. It is a negative feeling, yes, but you are not bad if you feel angry. It is there and you need to live it!
Someone who says he is not angry should feel responsible not to make the other one angry through his behaviour.