A Waist Trainer/Corset is a steel-boned, rigid garment designed to reduce the waist and reshape the body. Worn for centuries, corsets provide structure and support to the back and torso. With more frequent wear, the shape of the body may change temporarily.
 
Purportedly people wear corsets to help them slim down. This process supposedly "trains" your waist to a smaller size. However, corsets only make you appear thinner when you're wearing them – they do nothing to burn off belly fat. First season your corset and take short naps wearing your corset to get used to sleeping and laying down in your corset before sleeping in it for the entire night.