A term used for a female who is so obese that she cannot squat over a toilet properly to urinate without her ass hitting the back of the toilet and so she has to settle for pissing on the front part of the toilet seat instead of into the toilet bowl. A yellow puddly mess usually results as the bitch is usually too fat and lazy to clean up after herself.
Barbara cut down on the mac'n' cheese you're going to end up a yellow seat girl!
Ugh, piss all over the seat again in the KFC toilets. Damn these fat, slovenly yellow seat girls!