H.P.
My son has some oral sensory integration issues, and this one was a very hard one to break.
I finally started asking him if he needed me to bite him to show him how much it hurt.
If he continued biting, I would bite him a little, just enough for his face tos how a reaction. It only took one or two times of that before asking the question was enough.
I never just bit him back. I always framed it in the way "you don't seem to know that this hurts Mommy. I don't think you want to hurt Mommy. Do you need to know how that feels to me?"
He doesn't bite me anymore. He now only bites his "biting toy" which is a vibrating teether we got at Safeway. Now, if he looks like he needs to bite something, we get him that and he chomps happily on it.
He's 3 now, and doesn't need it as much, bit every now and then we need to break it out.
H.