That's one way to stop a dog from chasing you.

I found another good one the other day. I was past the "danger area" for the dog when it lit out after our group, but it was heading for some of the other riders behind me, so I hollered "Dog Left!"

And the dog left.

"Get a job" seems to work pretty well, too. Maybe it's just that a command to the dog tends to have some anxiety in the tone of voice?