How do you make the punch hurt badly?

Answer 1

There is a variety of ways. One way is to pull back your index and pinkie fingers so that your two middle finger knuckles stick out further.

Another method is to follow through with the punch and push all the way through, and not let up when you hit (pulling your punches).

Finally, you can also tilt your fist slightly forward so that your knuckles hit your opponent rather than the middle of your fingers. You want to be careful with this method though or you may jam your wrist, pretty much putting that hand out of commission for a few days.

-Para

Answer 2

Punch with your the 2 big knuckles remember that your power come from your feet shoulders and hip when you twist