If your baby starts to clamp down, you can put your finger in his or her mouth and take him or her off of your breast with a firm, "No." Try not to yell as it may scare the baby. If your baby continues to bite you, you can try a few things:Stop the feeding immediately so the baby is not tempted to get another reaction from you. Don't laugh. This is part of your baby learning limits. Offer a teething toy or a snack or drink from a cup instead. Put your baby down for a moment to show that biting brings a negative consequence. You can then pick him up again to give comfort.
This answer is based on source information from the National Women's Health Information Center.