I like to cause the type of pain that the body of my slave feels as pleasure and there are many of those if you know how to build to it. The pain only is rare for me, used to allow her to prove what she is willing to submit to just to prove to me that she is mine.

Punishment is rarely pain based for me, and especially if she grows to want that pain. Then instead of punishment it becomes a reward for bad behavior. If she finds that pain is a reward for her then that is what I will use it for, and never as punishment.