I have stuck with a loud ouch with Isabella. She started with her teeth on my hands every time I pet her when she was about 5 months old. It has been a long road, but she is catching on...it is SO much less frequent now. I say ouch when she bites at my hand and praise the heck out of her when she licks...she is catching on..finally! She is now one year old! So....hang in there! There is hope.