Also:
whale tail - the appearance of the top rear strap of a woman’s thong, v-string or g-string underwear above the waistline of her pants, shorts, or skirt whenever she sits, bends over or squats, though some low-rise clothing is now designed to display the whale tail at all times; so-called because the strap closely resembles a whale’s tail rising from the water.
and
Muffin Top (or Muffin Top Girl) is a slang term for someone who wears both tight fitting low-rise jeans (or pants) and midriff-baring tops. This phenomenon generally occurs when the wearer is overweight or attempting to squeeze into incorrectly sized pants and the resulting bulge of flab above the waistline is often said to resemble the top part of a muffin, where the dough spills over the casing.
Muffin