Karnapidasana is usually taken as part of a shoulderstand sequence after both plow and shoulderstand, but can also be useful on its own or to prepare for plow as it stretches the neck, hips, and upper body without having to worry about hamstring flexibility.
To begin, start in shoulderstand or plow, then simply bend the knees, drawing them in toward the ears. Those with limited hip flexibility will find it difficult to bring the knees in that far, and if that is the case, keep the hands on the back and bend the knees to a comfortable angle without compromising the spine. This will improve with time. If you are flexible enough to bring the knees all the way down to the floor by the ears, you can clasp the hands and extend the arms behind the back or wrap the arms around the legs and gently pull deeper into the posture.
To come out, extend the knees back toward plow, then place the hands on the floor and slowly roll down onto your spine. Take a few rounds of breath in Fish Pose afterward to help release the neck.
If you have any questions, please leave a comment below. I’d love to hear from you or see you at one of my classes!