I have been having problems lately leash training my CAO Kyhoon. He has a habit of stopping and just lying down. I tell him to come and he comes and I praise him. But despise this he will stop again a couple seconds later. This process can keep on going 15 minutes. At this point I can't really walk him. I have tried a choke chain it does not work. So could you guys help me with suggestions on how for him to become obediant on a leash?