Your dog must know the "Down" command in order to do this, but it is fairly simple to teach. Just
know that it will take a lot of practice.
STEP 1. In your right hand, have your treat reward. Place your left hand on top of your dog's back
directly behind the shoulder blades. Command "Crawl" and lure him forward.
STEP 2. When he tries to stand up, apply gentle pressure to his back in a down and forward motion.
Reward him right away when he moves forward correctly on his own. Once you have practiced this and he understands
what crawl is, you can try longer distances.
(If that doesn't work, you might want to try two people. One person can control Rover's position, while the
other uses the reward to coax him to crawl.)