Begin the training session by removing the doggy flap from the door. If it isn’t detachable, tape it into an open position. Find a friend to help you with the training, preferably a friend or a family member. The helper can keep your dog company inside while you sit outside.
One method is to call your pet’s name from outside and see how they respond. Have some dog treats in hand as a reward. Treats can do wonders for teaching your pup some proper manners.
He might run through the door, or he can be more fearful and retreat into his dog house. If he gets through the door, say “yes” and give him a treat. If he doesn’t want to go through on his own, your helper can gently push him from behind. Maybe your dog will come partway through the door. In this case, use positive reinforcement, but don’t give him the reward. It’s important to repeat this a couple of times and don’t do more dog door training that day.
Another method is the lure method. You can make a trail of dog treats leading from inside, through the doggy door, to outside. Or you can have your dog’s favorite treat attached to a toy. If your dog gets through the door, say “yes” enthusiastically and reward them. Repeat five to ten times.