[RogueNine]

If you can palm it off the dribble it shouldn't be too hard, just practice it running full speed and sweaty. If you can't palm the ball its trickier but not impossible, like someone said above you need to cup the ball with you with your hand and forearm, try it with both hands, I had an easier time of it with my left hand when I would practice. Start by just swinging to, or just past your hip, once you can do that comfortably starty putting it further and further behind your back. don't try and skip right to the full thing, perfect practice makes perfect.
I can't emphasize enough though; TRY IT SWEATY!!! otherwise you'll try to break it off in a game situation and the ball will slip out and you'll look like an idiot