I hate to be the bearer of bad news, but you are not very good at training your dog. When I got my first Rott, I had a neighbor down the street who bred Rotts and he came up to talk to me. He commanded his dog to sit at the corner a block and a half down and proceeded to come up and talk with me about my dog. Told me if I wanted any advice on how to train my dog he would be willing to help me. As we talked several people walked by his dog, some of them walking their own dogs, his dog never moved or even took his eyes off his owner. He didn’t move until his owner called him to come. Your point about it being in the dogs nature isn’t valid, it’s in a dogs nature to sniff other dogs and check them out, yet his dog never moved until he gave the command for him to come.