Portable Stomach
A device such as a back-pack or fanny-pack used at an All-You-Can-Eat buffet by questionable individuals who wish to take food home with them. The use of a portable stomach must be clandestine, users caught shoving food into it are usually ejected from the premises.
"Chuch went to the Old Country Buffet, but got kicked out when he was feeding the Portable Stomach"