Hello, we have a 3 month old puppy. He is 80 percent sweet and 20 percent naughty, lol! My question is....within the past week or two he has started biting really hard while we are playing with him. He will be fine and then just get super fiesty and snarl his lip back and lunge and bite and keep on lunging and biting until we get him under control. Is that normal behavior for a puppy? Other than that he shows NO signs of aggression what so ever...he doesnt guard anything or have any food aggressions or anything like that. I have two kids so its a fine balance of keeping everyone safe and happy! Any thoughts or advice would be greatly appreciated!