Complex sentence: Tightlacing (also called corset training and waist training) is the practice of wearing a tightly-laced corset to achieve extreme modifications to the figure and posture and experience the sensations of a very tight corset.
Split into simpler sentences: Tightlacing (also called corset training and waist training) is the practice of wearing a tightly-laced corset. It is done to achieve extreme modifications to the figure and posture or to experience the sensations of a very tight corset.