Here's a definition from the Urban Dictionary. And, by the way, Natalie has very little muffin top.
Muffin-Top is a word used to describe the strange and bizarre waist scrunching effect that results when females wear tight fitting, low-rise/hip-hugger pants along with small-sized, navel exposing, mid-riff tops.
Though, the effect is more extreme with heavier females, all females, with the exception of anorexic models, can fall victim to the muffin-top disaster. The reason for this, is that the design of low-rise/hip-hugger pants, originally popular during the late 60’s and early-to-mid 70’s, defies the natural shape and contours of the average females’ body; forcing the skin and fat around her waist, back and upper buttocks to spill out over her pants and through her tiny crop-top, causing a muffin-top effect.
