Matt Margetts says it best.
http://www.sbcskier.com/features_article?news_id=605
For starters you should be able to carve, do a straight air Tail Grab, land solidly switch, and have your 3s on lock. Find a jump more than three metres long, a halfpipe or a backcountry booter and get down to business.
There are two ways to do this trick: straight, pop, and dip a Cork Five or, like me, you can carve into it like a pimp. I’ll describe the latter: come in hands low and out front, aggressively with your shins pressed hard into the tongues of your boots on the far left of the in-run. Carve right into the transition, then carve left off the far right-hand side of the takeoff.
As you approach the lip press hard into the takeoff with both left edges. Be very patient and allow your tips to come off the end of the jump. Pop hard to your left side, almost touching the takeoff with your left hand, and your left ear to your left shoulder.
At 180 you can already see your landing because you’re so damned corked. As you takeoff leave your right hand low and behind your body. Cross your left ski over your right ski and place that right tail into your right hand that you left behind on the takeoff.
Grab that ski and hold on for dear life until you see the landing at 450. At that point you should let go, uncross your skis, and spot the landing over your right shoulder. Keep your feet shifted back to avoid over-rotation and rack up a bunch of extra style points. Make sure your knees are slightly bent and your body is in a strong and ready position for landing. Stomp and ride away looking over your shoulder, preferably your right— it’s smoother looking over the shoulder opposite to the direction you were spinning.