Oh, my yorkie definitely can be a little ferocious at times. When she doesn't know when to stop, I tap her on the head or butt and give her a FIRM "Bad dog, No!" and she puts her ears back and knows when enough is enough. And be sure to praise her when she does good things. Such as when she goes potty "Good girl/boy" and give a kiss. My dog has learned the potty training a lot quicker than i thought she would.
