Full Diaper

I. When you observe a female's ass through any of the following:

a. Yoga pants/Gym pants
b. Pair of Jeans
c. Swimsuit Bottoms (1 & 2 Piece)
d. Sweatpants
e. Daisy Dukes
f. Any other tight-fitting, thin material

At which point you notice a lot of buldging and lumps trying to escape the underwear underneath; hence the large mass closely resembles a fully loaded diaper.

"Babe, don't look now, but that lady over there has a full diaper."