a sock, usually knee high or similar, worn by an extremely tubby person, causing the the flesh to bulge over the top of the sock similar to breakfast muffin overflow.
Similar to a muffin top but occurring whenever sock constricts flesh and causes bulging overflow.
Rick: did you see that roller derby chick?
Dale: with the knee high socks..?
Rick: yeah, girl should rethink her sock choice...serious muffin sock! Gross!