For someone untrained, if you hit a human body with open palm (think slapping or spanking type hit), the hitter usually discovers that it hurts the surface of his palm and bottoms of fingers significantly more than expected.
Are there any exercises to improve this situation (lessen the amount of pain when hitting)?
I'm looking for details specific, so "hit something with your open palm" is a bit too generic.
What should be hit (something hard? Something with consistency of human body? Shape? weight? mobility of object being hit?)? How many hits in a row and how many sets a day to avoid actually damaging your hand?
Should there be some specific muscle groups that can be strengthened to help?