Sit in a state of Moola bandha and contract rectum and genitals by pulling up and raising the Apana Vayu (prana situated at rectum and discharge waste), to unite it with Samana Vayu (prana situated at navel responsible for digestion) and lower the Prana Vayu (air that keeps the heart and lungs working). With this the nectar of the group of the nerve centers of the yogis moves upwards to brain.