According to Wilson, this exercise seems to trigger neurotransmitters which he relates to the experience of "mother's milk" (i.e. the snug security of breastfeeding), and compares to opiate use without being dangerous or addictive. It will allow You to feel a light ecstatic state, along with some amount of the mystic heat of the shaman.
To perform the Breath of Fire, You will be taking several breaths via panting aswell as full yogic breathing. The latter involves inhaling from the diaphragm until the lungs are completely full. You will know You are doing this when your stomach, rather than your chest, fully distends during inhalation.
*Note: Keep in mind that a single breath involves both an inhalation and an exhalation.. whether panting or practicing yogic breathing.
Here it is..
Begin by lying comfortably on your back.
Pant rapidly through the mouth to the count of twenty breaths.
Then, perform twenty full yogic breaths - inhaling through the nose & exhaling through the mouth.
Repeat the process.
Simple as that.
As Wilson states.. the results are most amusing & enlightening.