I'm pretty sure Cesar Milan suggested this.

My dog signals that he wants to come in by knocking on the back door with his paws. He will repeat this once every thirty seconds for the entire night until someone answers. Sometimes, he will do this within three minutes of having been outside.

Like he just wanted to check and make sure everything is still where he left it.

Again.

So, sometimes, I just stand there in the warm house- maybe get down on eye level with him while he's knocking to come inside, so he knows I mean it, and whisper at him,

"No one is coming to get you. No one can save you now!"

Then I laugh maniacally.

So he knows I'm dominant.