This article by Paramhansa Yogananda is excerpted from the excellent book, How to Have Courage, Calmness, and Confidence.
In sleep, we experience sensory relaxation. Death is complete, though involuntary, relaxation of the spirit from the body. It comes after the arrest of the heart’s action. By the “Hong Sau” technique, one can reach the point of even relaxing the heart, and thereby rising above its compulsion to outwardness, experiencing death consciously, and eliminating one sense of the mystery of death and the fear of dying. One can learn, indeed, to leave his body voluntarily and blissfully, instead of being thrown out of it forcefully, often as a complete surprise, at death.
Inattention during practice of this technique can be soporific, producing sleep. Concentrated attention, on the other hand, brings to every body cell a tingling sense of divine life.
If you have the time, practice the technique longer—indeed, as long as you like. I myself, as a boy, used to practice it for seven hours at a time, and thereby achieved a deep state of breathless trance. Hold to the great calmness you feel during and after this practice. Cling to that peace as long as possible. Apply it in practical life situations, when dealing with people, when studying, when doing business, when thinking. And use it to help you to practice self-control, when trying to rid yourself of some deep-seated, harmful mental or emotional habit. Whenever a situation demands it, recall to mind the calmness you’ve felt during and after the practice of this technique, and, reliving that state, meet the situation from that calm inner center, where your natural soul-intuition will ensure the best possible outcome.
Remember, deep intensity of concentration is necessary for the correct practice of this technique. This does not mean, however, that there should be any sense of strain present. Practice the technique calmly, with relaxation—even with reverence—and feel in that calmness that you are placing yourself in readiness to listen to, and to become absorbed in, the Cosmic Vibration, AUM. Hong Sau will help to put you in contact with the Great Spirit, who is present in you as your soul, and whose expression is vibration, the cause of that inner sound. Results will positively come, and deep calmness will be yours. Higher intuitions will come to you after prolonged practice, and you will find yourself in touch with the unexplored reservoir of divine power.
Do not be impatient. Keep on steadily. Incorporate this practice into your regular routine, making it as much a part of your day as eating, brushing your teeth and bathing, or sleeping. Supremely beneficial effects will pervade your whole mental and physical constitution.
As in everything else, the highest results cannot be attained in a day or even in days. Practice! Practice the technique, and apply to your daily needs the calmness it produces. Remember also, I speak from experience—not only my own, but that of centuries of experience by the great yogis in my country. You, too, can have the same glorious experience as they, if you persevere in your practice.