Sometimes sold at 7 Eleven stores and popularized by Seinfeld. Also, cute and preppy young gay men who summer on Nantucket and prefer to be, well, on top.
Developed by me and a few friends, muffin top describes the fat that leaks over the top of a chicks pants when she wears jeans that are 2 sizes too small.
Muffin Top: The disgusting amount of flab which one cannot keep holstered within one's pants. Mainly needs a makeshift brace/belt of some sort. See also: Muffin Man; Weightloss; Disgrace to ones bakery.