Miranda bites me when she's mad or if I don't pay her the attention he wants. What I've tried doing is saying "OUCH" really really loud. That usually scares her and makes her cry and then she won't do it for a while. But it is just a phase. Could be that his gums are itchy or maybe he's just testing his boundries or wants to see what your reaction is going to be.
(DS used to bite me right in the butt...he used to come up behind me when I was doing the dishes and sink his teeth in. Funny now...not funny then.

)