In the same interview with EW, director Barry Sonnenfeld explained that Morticia’s appearance is inhuman, and unfortunately that means some serious behavior for Huston:
“Morticia has a shape that only a cartoonist can draw, so we strapped Anjelica to a metal corset to create the kind of hip and waistline I’ve never seen before. any woman in reality.”
The corset was invented in the Middle Ages to help define a person’s shape. They are typically women’s wear, although several types of men’s corsets have been (and are) in existence. Corsetry uses bones made from genuine steel or whale bone to force the rib cage and belly into a new shape. While the results can be visually appealing and some people find wearing a corset oddly comfortable because of the extra support in the back, there are countless dangers tighten his belt, something Huston had learned for himself after long days on set wearing tight-fitting clothes.
https://www.slashfilm.com/1043795/becoming-morticia-for-the-addams-family-was-an-exhausting-process-for-anjelica-houston/ Becoming a Morticia for the Addams Family Was an ‘Tired’ Process for Anjelica Houston