I recently heard when I do get a puppy, that I should never play tug or any win/lose games. I've never heard of this before. In all the dogs I've had I've always let the puppy win until their teeth were strong enough and they were old enough to actually play. I've always found it becomes their favorite. I also use it for training (drop it, rewards for recall etc) I did some googling and I guess it leads to aggression? Is this just a thing with mastiffs? Or is it an old wives tale. Thanks!