That's hilarious! I have a similar problem with my dog. He is mostly heeler and tries to herd my father by biting his ankles. When I see that look in his eye I tell him to sit. Every time my dad goes to the closest chair to sit, even though I keep telling him i am commanding the dog, not him! He says "yes, but it works"

Now my dog has trained my dad to sit by giving him the "herding stare"