i only put a leash and harness on him to take him out of his enclosure to go outside so he can run around a bit and get some sunlight and some exercise so he doesnt get fat and lazy.
i saw the videos on youtube of some lady letting a monitor feed from her mouth, she held a piece of meat in her mouth and let the monitor take it from her. there was another one of her demonstrating how she teaches a monitor to "give her kisses" for food. thats nuts to me, i wont even make my dog do that!
i feed my monitor using tongs, and he's a healthy growing boy! he has a hot basking spot and is truly spoiled.
if he hisses or thrashes about or is in shed i let him be. i want him to be tame and not overly aggressive, but i'm not going to leave him in a cool state or underfeed him so i get a sick, lethargic, "dog tame" monitor. thats cruel.
but i want to let him get exercise safely, so yes i put a leash on him so he cant run off. these guys are quick and can climb a tree pretty fast. i dont want him to get hurt or escape.