Failing all else, believe it or not there are tummy flattening clothes and accessories you can buy to hide or flatten your tummy - while you're wearing them of course. (although it won't stay that way once you take 'em off!) I've used tummy control hosiery many times. They work great and I found that they don't feel restrictive or uncomfortable.
You can dress to create the appearance of a flat tummy, whether you are slim and you have a 'mommy tummy' or whether you are overweight all over, by defining your waist with structured clothing items. When shopping for clothes, forget being hung up on the size, and simply go for the clothes that fit you well.
Wear a well-fitted, good supporting bra to lift and support your breasts and help to accentuate the smallest part of your waist.
Consider wearing a wide elastic type belt (rather than a skinny belt) to create the appearance of a narrower waist.
Wear wide belts together with a long white shirt, blousy top or dress or a longer button-down cardigan.
A wide hip belt can also be used with a long blouse or shirt to hide your belly.
Slightly tuck in long, blouses or shirts to create a sort of 'blouson effect' that helps to hide a mummy tummy.
Wear a fitted longer jacket with buttons, that ends just about your hips, to help define your waist but hide your tummy.
Wear well fitted jeans with a waist that is just around your navel to help keep your tummy in and are darker denim with a wider hemline rather than the 'skinny' or tapered leg.
Wear big extra large baggy t-shirts. They just make you look bigger.
Wear too-tight jeans that give you the 'muffin top' - you can see this one a mile away even under that baggy shirt.
Check these items out!...
The Cindy Tank Top Tummy Shaper
This 'girdle' is reported to help you get the figure you always wanted by lifting, shaping and slimming your body and flattening your stomach, waist, hips and back. It is made with latex fabric and features an exclusive design and is supposed to be ideal to wear under clothes and not noticeable.