I had a blow on one once. The result was rather like someone slowly pushing a piglet, snout first, onto a belt sander.
I guess it's all finger co-ordination, but the lips stuff is plain weird. Mind you, I'm one of the few sax players I know that really struggles to get even a note our of a flute, though someone once told me that's coz I started life as a trumpet player. Not as in, right out of the womb you understand, as that would have been a) painful for mother I'd imagine, and b) both surprising and irritating for the Midwife.