They are grooming you. Katiebug does the same thing...she will lick and lick and then nibble then lick, nibble...lick...bite. Usually not hard enough to break the skin but she is a tortie with tude. When she and I are having a minor disagreement about whether it is time for her to get down and she is throwing a temper tantrum I will ask her for a nose lick. She swipes my nose with a tongue and she gets to be let go. We both get what we want.