You've mastered the basics of dog training with your canine buddy--sit, stay, down--and now you're ready for one of the next level, the crawl. This is a pretty easy trick to teach a dog, especially one that is food motivated. Grab a few of your dog's favorite snacks and head to an open area either inside or outside and watch how easily your dog figures out what you want him to do. Be prepared to get down on the ground for a little while! And once he masters it, keep reinforcing it amongst the repertoire of his other tricks so he doesn't forget what you're asking him to do!
Head out to an open area. It can be a big living room with some floor space, or outside on the grass if there aren't too many distractions. Have your dog sit, stay and lie down. Reward with treats.
Hold a treat out so your dog sees it while he is in the "lie down" command. Go very close to your dog, right in front of him, and pet him while he's down. Get down on the floor with him, right in front. Give him a treat. Hold the next treat right in front of his paws on the floor. When he puts his nose down to the floor, give him the treat.
Take out another treat, and bring it down to the floor. The dog's nose will go right to the floor. Pull the treat back toward your body. The dog's neck will follow you. Say "Crawl." Creep backwards a tiny bit. The dog may shuffle forward a bit in a crawl. If you can, give him the treat right away. You might not catch him in time before he stands up to move toward you. If he stands up, you have to place him back in the down command and start again, pulling the treat back toward you until he stretches his neck out, and eventually has to creep forward.
Repeat until you can get your dog to inch forward a tiny bit without getting up. Reward with a treat. Inch back further and have him inch toward you again. Reward immediately. Do this until you have crossed the room. You might quit for the first day here.
Repeat the steps you taught him yesterday. Then put him in the down position, squat down, not quite as low to the floor as you were yesterday, and hold the treat down to the floor. Pull the treat back toward you as you walk backwards a step. Your dog should inch forward. If he even looks like he's going to get up, repeat "Down," and "Crawl" as you pull the treat back towards you. If you go back a step each time he gets too eager, he'll eventually get the idea and stay laying down. By the end of this session, you should be able to back up slowly, dragging your treat backwards while saying "Crawl" and your dog will scoot in the crawl position following you. Make your goal only a foot at first, and work your way up to all the way across the room.
Repeat the earlier process the next day, then try using the "Crawl" command from standing up. Hold your treat aimed at the floor, level with your index finger as you point at the floor, saying "Crawl" and moving your finger down and backwards toward you. If your dog makes even one little scoot, reward him. Then take a step back, have him crawl again, 2 scoots this time. Reward him. Pretty soon you can back up across the whole room pointing down at the floor and he'll follow you by crawling.