To teach a dog to stay, you stand beside the dog, say, “Stay,” pivot so you are standing right in front of the dog, then pivot back into your original place (standing beside the dog).
Next, you do this whole sequence but when you are in front of the dog, you step back one step. Then, you practice moving back 2 steps, then 3, until you can eventually tell the dog to stay as you back up to the end of the leash.
Remember, being able to back up and return to the dog is not the end of teaching stay. When the dog is reliable on stay as you back up, you have to practice walking away from the dog (with your back to the dog), leaving from the side, and so on.
Otherwise, you end up with the “Walking Backwards Stay” that we sometimes see in CGC with beginning trainers. The owners who do the “backwards stay” leave the dog by backing up a step at a time with one hand rigidly held in front, palm facing dog, like a policeman who is commanding, “STOP!” They tentatively back away as they plead, “Stay, stay, stay, stay, stay, stay, stay….”
When you see this, you’re seeing a dog who needs a little more training on stay and an owner who needs a little more confidence.