A cummerbund is a broad, pleated sash that wraps around the waist, usually as part of a tuxedo. They add a flash of contrast to the shirt and trousers, and can give an opportunity to add unique colour.
Cummerbunds are easy to wear. Simply wrap around the waist over the meeting of your trousers and shirt, and lay the jacket over the top.
A cummerbund has a natural, bowed shape. The arch and pleats should always point downwards.
Suspenders should always sit under the cummerbund - part of the function of the cummerbund is to cover the utilitarian clips and buttons.
Cummerbunds these days often have an adjustable strap and a clip fastening, making it easier than ever to wear a tuxedo cummerbund. Simply wrap it around your waist, adjust to fit and fasten it up.