Hip Lift

The hip lift helps to strengthen and stretch the entire pelvis.
For a more dynamic exercise do not hold the leg with the hands. 
Push the knee of the crossed leg away from you, and a pull the knee of the bent leg (not crossed) toward you.  There is no motion in this stretch. Just the push -pull -hold.  Do not use your arms to pull. Relax the neck.

Hold this position for 1 minute on each side. 

You may feel completely different on each side, that is a sign that you really need this stretch.