We've had a dog do this, we squealed when he bit, as if he'd broken skin and we were really hurt, we then stopped playing and turned out backs on him. It took a little time, but this worked. Also giving lots of chew toys. We offered our finger, if he bit too hard, back to squealing and not playing. He soon learnt to bit gently.
Hope you fine what works for you.
__________________ Caleb   Pippi |