you do NOT need to inflict harm on your poor baby!!!
andrea s is right on with the pulling baby into the breast instead. my son hardly bit at all when we did that (and he chewed on EVERYTHING, still does at age 2).
when she's older (and getting in canines or such, which are tougher on them) and does it, you can unlatch and say "mimi doesn't work when you bite. biting hurts mimi (or whatever you call nursing in your home)" and end the nursing session temporarily. after a few seconds or minutes, resume nursing. believe me, it only takes a couple times before they stop biting the boob that feeds them! ;) (and once again, you are not inflicting physical pain on your child)
i'm a sahm to a nursing toddler boy of 2.