School of Yoga explains Gomukhasana (Cowface Pose)

Gomukhasana technique :

Sthithi (starting) position: Sit on the floor. Keep legs straight ahead and hands at the sides.
Grab the left foot with both hands. Guide it over the right leg under under the right buttock.
Lift the right foot over the left thigh and place it close to the left hip joint.
This is veerasana
Take the right hand over the shoulder.
Slide the left hand behind the back and try to couple it with the hand over the shoulder
This action will force the spine into a reverse arch.
Thrust the face up like a cow to stretch the cervical region.
Maintain shallow breathing if unable to sustain a “breathing out” situation. Hold 3 to 10 counts.
The drishti for this asana is oordhva drishti (gazing into space or ceiling)
Slowly, release the pressure on the back and bring the feet closer to the face
Breathing in, lift the legs and bring them back to the ground. Straighten the body
Breathe deeply. Repeat 3 to 6 times.

This asana benefits conservation of seminal fluid and activation of the svadishtana chakra..
The reverse arch results in strengthening of the entire spine.
Also, this asana strengthens the sympathetic and parasympathetic nervous system.
This asana is very good for resolving issues regarding menstruation.
There is enormous strengthening of the lower respiratory tract when one combines ujjeyi pranayama with this asana.
In the final pose, where there is a reverse chin lock, the stretching of the cervical region increases blood supply to the thyroid and improves functioning of the endocrine system.

People with cardiac or hernia problems should attempt this asana after first consulting a physician.
People with lower back problems must perform this asana only under supervision of a physician.
Do not perform this asana during menstruation or pregnancy.