Hi All. MuShu is almost 6 months now. He does fine wearing his collar. However, as soon as I put the leash on, he FREEZES in place. I have waited for him to walk so I can follow him; NOPE; and I tried gently tug on his collar to get him to move, HE WENT NUTS. Jumping up and down like I was torturing him. I have tried it so many times, he just won't walk on the leash. What am I doing wrong?