im not flexible and i got them.
several important factors:
a good air sense; being aware of where you are in the air naturally (or more so) so you can focus more on the grab at hand, rather than a spin or location in the air.
practice practice practice/repetition. get your body used to trying them. it might take a good few tries to get them. once you start getting them, get some muscle memory by doing them more and more.
and stretching also helps. before skiing, after skiing, and in free time.