Well, it's one of those inverse-correlation things, you know? The more effort you put into getting the lighting right when you shoot, the less effort is required in post-processing; and vice versa.
While it goes without saying that it would be reckless to just take a normal everyday photo of a belly and rely on some very advanced editing skills to turn it into this afterwards, I think it's also true to say that it would be unreasonable to expect to nail this perfectly in camera. Some editing will be involved.
Because there is no hair in the photo, you don't need to worry about a black background when you're shooting. That can be easily dropped in in Photoshop.
So when you're shooting, concentrate on the subject herself. Shadows in front, and that nice rim lighting.
As long as you have shadows in the right places, you can darken them further later, so don't get hung up on making them fully black in camera. That's what Levels is for.
Hope this helps. Once you take the Levels Class, a lot more about this will be clearer to you.