i have been trying to think of it as like a high speed worm turn except popping a little bit and dragging your hands instead of your body, at least off of knuckles
I learnt them sitting down first, then got them standing up by kinda carving in hard left and popping hard onto my left hand down and throwing my right hand kinda behind me if that makes sense.
Kinda similar to a cartwheel, find comitting to getting the right hand properly behind you is crucial.
Vid here;
=youtu.be if it's any help.
They're actually super easy and really fun tricks to do, probably my favourite trick in the limited selection I have down.
to kind of build on the post above me. carve hard, and as you take off the lip (like as your skis are leaving) reach back for the ground. It will drag your hands and set your rotation