For me, when I go for a flat, i'm really not in a hurry. I really take my time to pop, throw my left arm towards my ass and even though I don't always get it right, my right hand comes near my left shoe because it actually helps positioning your right arm. And lifting your legs helps the motion of the trick.
And it's when my right hand reaches my left foot (or nearly) that I know it is time for me too search for the landing. So turn you head and your body should follow. It's a scary trick, but relatively simple.