Most commonly you’ll find this waist sash in black tie or semi-formal men’s suiting. It is usually not used with white tie formalwear, the most formal of men’s dress clothing. White tie wear tends to call for a special waistcoat instead, which would make cummerbunds awkward. For semi-formal events when men wear a tuxedo coat, matching pants, tie and dress shirt, the cummerbund may be worn to add a little flash and flair to an outfit. It can also hide the faults of the rented suit that doesn’t fit perfectly. You’ll see many a cummerbund at events like proms.
The cummerbund can be a very simple pleated sash, with either a buckle attachment or an elasticized back. Some men choose a waist sash that has lots of color, patterns or design to individualize their wearing of semi-formal clothing. While it’s fine for a cummerbund to exhibit some color, this should coordinate with the color of your tie. In fact, matching cummerbunds and ties are quite common.
Most designer in men’s formal wear fashion such as Polo Ralph Lauren is devoted to introducing new styles of cummerbunds, but if you plan to purchase one, it’s a better idea to find one that is more traditional. A red, gray, or black sash is a better choice if you’re purchasing one for more formal occasions. But if you are wearing a cummerbund for a more formal event, it’s better to choose one that is subdued in colors or pattern. For the most conservative black tie events, the pleated waist sash should be silk, not the less expensive polyester satins frequently rented with tuxedos.
Traditionally worn with a dinner suit, a cummerbund has no specific function, beyond helping the wearer to stretch the legs and even making the wearer to look taller and sleeker.