Manduki Mudra
In Sanskrit, Manduki means "frog" and Mudra means "gesture." This Mudra is a Kaya Mudra meaning "postural gesture" practice and is described in the Hatha Yoga Pradipika, Gheranda Samhita as well as the Shiva Samhita. This practice is also preformed in Kriya Yoga.
This Mudra is described as a practice that gives the practitioner the ability to have eternal youth. This practice gets its name from the resemblance from a sitting frog.
The goal of this practice is calm the fluctuations and disturbances of the mind while bringing a balance to Ida and Pingala Nadis meaning "energetic pathways."
Practice
Preform Bhadrasana or gracious pose with the toes pointing outward.
The buttocks should rest on the floor.
Bring the hands on the knees while holding the spine and head straight.
Close the eyes and relax the whole body.
After some time, open the eyes and perform Nasikagra Drishti Mudra.
If the eyes become tired relax them for a minute or so.
The six cleansing actions are intended to be the start of a Yoga practice in order to clean, strengthen, remove toxins and improve the flow of Prana through out the practitioner.
Yoga poses help to elongate and strengthen the muscles of the body as well as to calm the mind for the deeper spiritual practices of Yoga.
Breathing exercises are a great practice to remove carbon dioxide, increase lung capacity as well as being a good preparatory practice for the deepest spiritual practice of Yoga, Meditation.
The four body locks that makes up this practice give the practitioner the ability to hold or lock Prana in certain locations of the body. These practices also allow the practitioner to release blockages that may be holding the practitioner back.
The gestures in this practice include the whole body and are intended to awaken Prana, Chakras as well as Kundalini energy within the practitioner.
Meditation is the highest spiritual practice of Yoga which is why this practice is the most difficult practice to preform, but with correct knowledge and dedication, can be the most profound practice of Yoga.