The few times I have done it, it was fun. What I find difficult is to know what knots make up what style of bondage. As far as doing it on a real person, a manikin doesn't compress like a person does. When wrapping the breasts for example. They compress, and push out. Turn colors. A plastic model wouldn't do that. For concerns of safety. Just have a good set of sheers near by that will cut through the rope.
In the attached picture you can see the girl I have bound, her left breast isn't tied as much as the right. Not sure why, but the rope didn't wrap around the left in the same way the right did. The discoloration you see happened inside of 10 minutes of being bound. Now is what I did considered Japanese bondage, or just bondage. Don't know really. Just did it, and had fun.