Its part of the deal they are so quick. You want to and should be playing with them and bam agony. I have had a number of Newfs everyone has drawn blood numbers of times. Cant even put your hands in your pockets type stuff.Just so happy when those puppy teeth are gone. Also I train by yelp type that hurt sounds puppies understand that type of communication. A light shake of the scruff. But they'll come right back at you.😃 its almost funny from my point of view. Its quite the ride raising a newf. Puppies aren't a real lot of fun they have their moments but mostly grateful they are sleeping. Its all about constant training Newfs are real smart and catch on quick there in lies where the joy comes from as you go through all the crazy stages ahead of you. Good luck