Many Yoga systems use this pose as the final asanna. It helps to stabilize the spine after all the various asannas, in addition it stretches the abductor muscles of the thigh and also the muscles of the pelvis. It is important not to force yourself to stretch beyond what your body can do without strain---in any of the exercises! Look at the three versions below. The first one [with the lower leg straight] is the one demonstrated in the class. You may need to do an even easier version and will be given help if you need correction in any of the poses. Please alert me if any of the exercises are uncomfortable in any way.
This is one of the versions we will do in class. The most important focus is to keep the spine straight with the weight on your legs to avoid sitting on your tail bone. Most people will need to sit on the cushion to achieve correct alignment. There are other versions we will explore that may be more comfortable.