Hi Jenn, I don't know why it is but some human males seem intent on arm wrestling dogs and rough-housing them. This is not good! Ever! Most men have no concept of their strength, also in dog language the grabbing of legs and scruffs is a very aggressive gesture its what stud dogs do in a fight. Tell him to think of non-contact hockey when he wants to play with the dog and remind him that one day he will be 100lbs of hooligan whose respect for humans might be diminished if his aggression is heightened in rough play.
Rose ps there is a lot of soft cartilage in an 18week old puppy and the joints are not hardened off yet.
