This is similar to the crossover stretch in the Deep Tissue Massage DVD, except that it is done with the client supine.
Lift your client's opposite leg up and toward you, cradling their calf on your forearm. Press on their ASIS to hold the hip to the table, then stretch their leg to the side, and up and to the side. Go slowly and stay within your client's comfort range.
Thanks to Robert Hall for this technique.