They get over excited, mine does it a lot, and she's a little lady

Brummie
x

Is he going for blood? That may be a sign that you are petting him
harder than he wants, or hitting a sensative spot... check his skin if
you can narrow down the area that causes the bite reaction... If he
doesn't seem to be going all out in the biting, then it could just be
a gentle way of saying the above, or like the other person said, it
might just be a little over-excitement. ~Ed~
~Ed~
"If it doesn't hurt, I'm not doing you any good."

My cat is really sweet,but he does the same thing. I think that it his way
of saying enough affection.