Upper body in the folded up position (like in the 100's). Right leg bent and left out straight on a diagonal. Fingers interlaced behind your neck, elbows out to the sides.

Exercise:
Inhale (through nose please) sending the air to the sides of your ribs to set up the breath.
Exhale and turn your upper body to the right, strive towards the right knee with your left shoulder, NOT with the elbow. Really rotate your spine and don't pull with your hands. Look back toward the back elbow and make sure you don't loose your wide arm position.
Exhale again as you switch legs and turn the other direction. Inhale and turn again, and inhale turn again.
The speed is pretty fast, turn for 6-8 reps. (4 in/exhales is 1 rep).
Variation: do the exercise slower, exhaling at each turn and holding that position for a few seconds. Try to get up a little higher than the picture shows. Inhaling on returning to a neutral position with upper body folded up and both knees bent. 6-8 turns.
Think about:
Keeping your arms and shoulder in a static position and let the movement come from the power house. Really try to get the shoulderblade that you are turning away from, to come up off the floor.
Lift up with a LONG rotating spine so you don't compress it and bend up.
Make sure the stretched out leg is really reaching in a diagonal, holding it on a height level that feels good for you. You can pinch you butt to control the leg.
Also, don't rock body from side to side when you are criss crossing the fast version, make sure that the power house is working to keep you stabil.