Instructions
Train your dog to sit on command before attempting to teach lying down. Having this basic command at your disposal will make the training much easier.
Call your dog to you, or put it on a leash if necessary to keep its attention.
Lower yourself to the dog's level. For small dogs, sit down on the floor.
Command your dog to sit down to begin training, and before each repetition.
Hold a treat in your fingers in front of your dog's face so it can see and smell it, but can't eat it. If the dog leaves the sitting position to try to grab the treat, start over.
Move your hand down to the floor. As the dog moves down to follow the treat, say "Down," to mark the behavior with a name. If the dog won't follow the treat at all, try another kind of treat.
Release the treat when the dog's entire body reaches the ground. If your dog only hunches over instead of lying down, slowly pull the treat away from it on the ground to encourage your pet to straighten out.
Repeat the process several times each day until your dog reacts quickly and without error.
Reduce your hand motion to smaller and smaller gestures, while ensuring the dog still understands the meaning. Eventually, the verbal command "Down," can replace the motion entirely.
How to Make Dogs Lie Down
The "down" command comes in handy for gaining control over your pet -- if your dog will lie down on command, you can use that command to interrupt other inappropriate behaviors such as barking or chasing. Lying down also helps get your dog in position for grooming. Training your dog to lie down consists of two basic steps: luring your dog into the proper position and rewarding that behavior.