I took Tinker to a behaviorist awhile ago, and she said it wasn't a problem. She told me to make sure if we are playing with a toy to only shake the toy side to side or up and down, but not pulling it toward you when they pull it away from you. She is an excellent trainer, and she was doing it with her dogs when I was there. I think it is just a yorkie thing. Most yorkies have little attitude, especially the little girls

. I think when Tinker acts like that it has to do with me not playing with her enough sometimes. They are so hyper that if you don't wear them out at least once a day they just don't know what to do with themselves. If you feel that it has become a problem I would go see a behaviorist at least once so she/he could give you some pointers. I did and it helps.