It's a Shamanic death ritual. Wash your entire body with salt and hyssop while you pray to your Tulpa. Dress yourself in the clothes you'd like to be buried in. Lie down in a comfortable spot where you will not be disturbed even if you stay there a week. Imagine yourself being buried underground. Imagine the world without you, as it spins towards its own eventual demise in the distant future.
Lie there thinking of these things, and do not move, speak, drink water, or eat until either 1) you are dead 2) you are ready to live. It works. Good luck.