That piece of extra skin that hangs down from a domestic or wild cat's belly. Some say it is to help the cat run faster. This loose flap of skin on the abdomen helps the cat stretch out further with each stride. Some say it is extra skin in case the cat has to binge eat and store extra fat in the wild.
The bengal's fast flap helps it run faster, up to 30 miles per hour.
de Rosie v B 14 septembre 2013