It's a reflex because of nerve endings. It's kind of like you scratching an itch which you cannot reach - or a spot which is ticklish for a human. It's not causing them any pain, the twitch is involuntary and is a side effect of the dogs enjoyment!
The "leg spot" is a common phenomenon in dogs. When I was a boy, we had a dog that had a "tongue spot": scratch him there and his tongue would stick out of his mouth!
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.