Skid mark

[PussyCat]

an elongated stain in the rear of ones underwear caused by one of the following: 1)rubbing of the underwear on an insufficiently wiped anus after excrementing 2)expelling juicy farts (butt cheese) into the underwear over an extended period.

[Couch Potatoe]

Also known as [a Connie] [lee] .
A black chunky line of poop left in the [crutch] of someones under wear after not wiping there bums properly.

[Renato]

When someone does not wipe all the [poopies] [out of there] butt after a shit and it [stains] there underwear.

[Greta]

A fecal stain that is visible on ones undergarments.
Also presents in a less structural (and lesser known) form, typically developed from excessive dry farting. In this form, the [skidmark] develops in a larger region, yet its definition is not as clear. Essentially, it is representative of a consistent [gaseous] pounding of ones underpants over a long period of time, and while fairly rare, is unmistakable. Usually, this effect is [understandable] to about 1/10th of all humans.

[Merna]

n. [Poo poo] stain in [the seat] of ones [underpants].