If the slimming undergarment is too loose or too tight, it will either not work or make the body's appearance worse. It can twist, have no effect, or be uncomfortable to wear. To fit the body shaper correctly, pull up the slimming undergarment, while unrolling the shapewear, until the point is reached where you want the plus size body shaper to work.
Then sit, bend, and stretch, to make sure it is comfortable while you sit and stand. If the waist moves or rolls, this may be a sign that another size is needed or that the body shaper is worn down and needs to be replaced. Ensure the slimming undergarment is void of wrinkles and bulges, especially paying attention to the crotch area.