How to do: Sit in Sidhasana, draw the tongue out in a tube-like shape and inhale through the tongue. Retain the breath. Draw the tongue in and perform Yoni mudra. Exhale through the left nostril. Again do the same and exhale through the right nostril. Do it several times.
Benefits: This Kaki mudra cools the body, removes excess of bile, purifies the blood and develops the mystic vision.