Muffintop

[PussyCat]

The effect of a fat girl wearing jeans tight enough to make the fat around her waist spill over the top of her jeans.
Usually noticed because the offenders clothing reveals their midriff.

[Rihanna]

The belly/hip spillage over the top of the jeans, forming a muffintop. Usually in reference to females.

[Tina]

A roll of fat visible above the top of a pair of womens tight-fitting low-waisted pants.