Thanks Playfelt! I asked the parents and yes indeed, the dad play nibbles and kisses child's belly, back, neck, arms, etc. He has agreed to leave the mouth out of play both for himself and the child. Hopefully that stops the biting before it becomes a habit. So far I have been able to intervene and stop the couple of attempts that have happened in the past two days since the initial biting. He is now under my constant watch and will remain so for the foreseeable future so that nobody gets hurt.