How to do: One has to first perform Mula bandha and press the Kanda(space between anus and the generative organ) by the right heel.Keep the left leg straight. Bend down and hold the big toe of the left foot with both hands. Bring the head down until it touches the knee. This position is also known as Janu-Shira-Asan. In Maha mudra, Janu Shira Asana is associated with the Bandhas, and pranayama. Inhale and while retaining the breath performJalandhar Bandha Bandha . Then Exhale while performing Uddiyan Bandha (taking the navel forcibly towards the back). Perform the pranayama as long as you can.
The same can be repeated by keeping the right leg straight and by pressing the Kanda with the left heel.
The gaze should stay between the eyebrows(bhru-Madhya Drishti). Meditate upon the Ajna Chakra.
duration :This mudra can be done as long as one can.
Maha mudra should be followed by Maha Bandha and Maha Vedha.
Benefits: This exercise enables the combined forces of Prana and Apana to pass through Sushumna, which awakens the Kundalini. This cures Hemorrhoids or piles, gastritis, constipation, consumption and various morbid conditions of the body thereby augmenting digestion and toning up the nervous system.
I think this mudra is helpful for you.Also, read my book “Complete Hand Mudras.” It will give you more information about mudras read more