When the tongue is folded back and into the cavity toward the skull touching the tip of the tongue to the uvula and eyes fix on the spot between the eyebrows, this is known as khechari mudra.
Now, what means khechari mudra? Word khecari comes from the Sanskrit roots khe, “ether” or “space” and charya, “one who moves.” This “moving in the ether” has a double meaning, as the scripture quotes: the first refers to the fact that the tongue move in the hollow space inside the cavity of the pharynx, and the second refers to the fact that mind remains in a state of complete stillness and inner peace. Khecari mudra is also associated with amrita, the nectar of life can elect which is secreted by the bindu, a point on the posterior fontanel, which is consumed by the throat chakra vishudha. In khechari mudra, you don’t need to cut the lower tendon of your tongue.
1 – There is no need to cut the “brake” of the tongue to perform this technique.
With the right practice and the continuing goal will be achieved without any risk;
2 – Sit in a meditative pose;
3 – Relax your body, close your eyes, directing them to the middle of the eyebrows. Leave your mouth slightly open and slowly lift your tongue back toward the hard palate and then to the empty area of the pharynx. Stay that way for as long as you can without discomfort;
4 – Breathe in slowly through your nose, resting in the sequence.
My yoga teacher said “USE THE POWER OF VISUALIZATION, THAT IS THE KEY TO khechari mudra”.