Sounds like you are getting the right kitty message. When little kittens play, they often start out by mock-attacking each other. They learn from mom cat or siblings how to keep from biting too hard during play.

One of my cats actually will gnaw on my fingers as sort of a calming behavior. He is not trying to "eat" me, or hurt me, but those teeth can be sharp! If he gets too rough, I just stop playing and move away from him. This hasn't stopped him from doing it, but keeps things from getting hurtful.