everytime she does it, have make a shrill sound and pull his hand away. This is rabbit talk for "you are hurting me, I don't want to play."

I wold get your rabbit neutered or spayed as soon as possible. That usually does the trick, making for a sweeter tempered rabbit. Then you have to think why a rabbit bites. it doesn't bite just for fun. A rabbit is a ground prey animal, so often it will bite from fear, fear of a big human predator or from being lifted and not being held securely. Does your son know how to lift up a rabbit properly? And for some smaller children, it's hard for them to make a rabbit feel safe in their arms. And to put it down? I'll post two videos here that show how to do it. If your rabbit bites as a way to express it's possession over things, like around it's toys or food dish, cage, etc, then you might use something to distract it, like a favorite toy or some hay. It could also be from boredom and it may need more toys or being played with, exercise. They often bite because things aren't going it's way and they want attention..NOW!!!! But many of these problems are due to hormones which would be better if it was fixed. Here is a page that talks about the aggressive rabbit that you might find interesting. http://www.wisconsinhrs.org/Articles/The%20Biting%20Rabbit.htm

what you should tell your son to do is when the rabbit bites him tell him to SCREACH as loud as he can and that will be a sign to the rabbit that he is hurting him. rabbits also screach like this when they are scared or hurt.