Bliss of Inner Fire, it's written by some Lama. This isn't really all that hard. So the idea is to sort of ignite the chi in your blood which sounds strange, or gross, among other things.. I think it's better to take it in steps, so the breathing techniques don't have to be followed to the letter just about 75-85% and set intent. The one that worked best for me causes serious bliss sensations along with the heat and i've read that a heel under the perineum can help push this meditation along but I can't sit comfortably in half-lotus. The first steps I had to master were only basic meditation rules I didn't know prior to jumping into this.