My baby is almost 6 months old and he has gotten WAY better with the nipping. At first i tried the ouch thing but he was COMPLETELY unphased by it. I just say No firmly and then give him a toy and praise him when he plays with it. Puppies chew on everything... i think its MOSTLY a phase and they grow out of it- we hope! He is teething really badly now and i know it. He tends to nip most when he is really excited but generally when i play with him i can tell he is careful to avoid nibbling my hands when he grabs the toy. I have decided he is a genius.