This was an ad on the Montreal metro. The closest thing I can think of is a manzier, but upside down. Maybe a morset?
It claims to improve performance during exercise. The website claims that it is a “Gym waist trainners 2 hooks” and that, “The latex material will make you sweat to burn more localized fat.” I can’t wait to see what ads Google feeds me now that I’ve visited that page.
Amazon.com has 18,993 results for “male corset.”