Interesting! So partial hanging isn't done by just by blocking the circulation in the neck as most people try to do, because this will mostly close the veins and not the arteries (which are deeper in the neck), causing the feeling of pressure in the head.
It seems that it's done in 2 steps. Correct me if I'm wrong. First the circulation is stopped by putting pressure on the neck with the rope. Then when there is a feeling that the head is "exploding", due to blood collected in the head, it is important to stand up and release all the pressure quickly. This will cause fainting, hanging unconsciously on the rope and presumably death.
My doubt is that death is not ensured, or that one could hang for long before eventually passing out due to lack of oxygen in the brain. There is no control of what happens after losing consciousness