Shop › Waist trainer Image 1 of 1 Waist trainer $29.99 A waist trainer is a shaping garment that wraps around your torso it is designed to give you a sleeker, smaller waist by pulling in your midsection tightly by stimulate thermal activity in your core, making you sweat more during exercise. Quantity: Add To Cart Added! A waist trainer is a shaping garment that wraps around your torso it is designed to give you a sleeker, smaller waist by pulling in your midsection tightly by stimulate thermal activity in your core, making you sweat more during exercise.