RadDad asked me to help out here, and I'm not one to deny the great RadDad! Here's my backwards cliffhanger. Its a little sketchy, going backwards, and the parking is sort of narrow for me on this one, but it still counts!
My best tips for this trick is, first you want to learn how to roll a backwards hang 5 really well. Then roll a bw hang 5 with your seat out front, your butt b/tw the wheel and seat. Learn to roll that really good. Try to line your body up nice and centered with the axle, and try not to bend over too far over, keep your shoulders up. When you can feel the balance of your body and frame rolling together, bring your free foot in and step down on the peg and let go of the bars. If you can get a good bw hang 5 roll with the seat infront you're well on your way.
I do it with my bars backwards because it's hard for me to push the bars down far enough to get my butt behind the seat. It made a big difference for me, it's just extra weird when I half lash to ride out. If you're taller than 5"5 you might have an easier time.