Wiktionary
n. 1 Something that cinches as in holds and fastens, such as a belt or corset. 2 Something that proves a point or concludes a story 3 A waist cincher (type of corset).
Wikipedia
Usage examples of "cincher".
She slipped her arms into the sleeves, tugged the insewn waist cincher together in front and threaded the lace through the grommets.
She wore leather hip boots with long, sharp heels, shoulder-length leather gloves, a black waist cincher, and nothing else.
Sooner or later most of us wound up using cinchers or something similar.
I'd start with him humping some customer like a wild stallion, and afterward, while she's in the bathroom fixing her makeup, I'd show him making sure the cincher was in place, maybe wipe away some blood, and then posture himself so that when the woman came back to the room she couldn't see that he still had an erection.