It is defenately a play thing. Maxi does the same. My boyfriend likes to make him all crazy running around and wrestling with him and I dont. So when Maxi was trying to do that to me I would say no and cry and make my hand limb he would understand he hurt me and give kisses. Now I play with him too with a little wrestling but he knows to be gentle with me otherwise I would do that trick again and he really doesnt want to hurt mommy
When he is about to get wild I say Maxi please play nice and usually it works
If you want to stop this behavior you have to defenately say ayyy that hurts and sort of cry and make your hand limb and then ignore the pup for a minute or so. Usually they get the point
Good luck!