hi. i can't suggest much else i'm sorry. i used to hook my finger in their mouth and take them off and start again, take them off, start again. never put them down and walked away. if you try keep stopping and start straight away he may get fed up off keep stopping and starting and stop biting as they don't want an interrupted feed. is he biting quite early in the feed or later. if later, he maybe playing cos he's full now he's on solids and is really feeding for thirst and finds biting you amusing or if early it could be soothing his teeth!! but he needs to know your not a soother! this worked for me, with both my girls who i fed until 15mth but it took while and if you want to keep feeding you'll have to stick with it.