fastening corset

The act of manually closing a corset by pulling its strings, typically to make a person's waist appear smaller. To fasten a corset can be part of dressing.

To unfasten (take off) a corset, you do not pull the strings, instead you untie the knot and then my pull the sides of the corset, away from the wearer.

• Danbooru post #945821: example of unfastening (the opposite of fastening a corset)