What's the best way to stop a baby who breastfeeds from bitting/playing with the nipple?

There are few reasons baby bites/plays with the nipple: 1. Biting at the end of a nursing session: baby normally is full already/not long interested in latching. Do watch for signs of boredom, and take baby from the breast before the biting starts. 2. When baby is teething: offer him/her a teething toy and tell him this is for biting, please be gentle when nursing. Repeat this for few times and he will get the idea.