This is a variation on a technique from the Deep Tissue Massage DVD called Torquing.
Sit on the table with your foot underneath you, off the edge of the table. Have your client's arm draped over your knee. Pull back and down (inferior & posterior) on your client's shoulder while pressing up (superior & anterior) on the opposite side of your client's spine. Press first with your hand, then the ulnar side of your forearm.