At a medium/slow speed carve hard and roll onto your side. You need to pull your knees and legs behind you so your skis don't catch on the snow. Roll along your stomach and onto your other side and if you have enough momentum you can get your skis under you again and stand up.
They're really not that hard and if you practice a bit you can do them while you're going pretty fast and you'll pop right back up onto your feet.
Hmmm so what is it called when you set in a spin and tuck on the snow until you spin around enough? Like you spin on your side. Kinda on your shoulder/side. And the rotation is almost like a backflip... This might be really unclear but I don't have video of what I'm thinking of. Is this just another variation of a worm-turn?
Note that in the worm turn, the skier slides on his stomach, as though he were doing a hand drag with his whole body, whereas in the polish donut, he stays on his side throughout the duration of the trickery.
What the fuck were you doing?! One looks like a failed abortion and the other like something from chicken run. - ski-plastic