From Open Lizard, draw the right knee back in, shift weight back, bending your left knee and straightening your right leg (the photo illustrates the other side).
Fold toward your straight right leg coming into an easier variation of Split. If you need more of a stretch, inch the right heel away from you, lowering the hips toward the ground.
You by no means need to go all the way down into a full Split! Hold wherever you feel a deep stretch in the right hamstring for five breaths.