Dirty Laundry
I wore the same underpants for 7 weeks, not washing them. I wanted to see how long i could do it for. I wore them day and night, only took them off to shower.
Im 17 and the longest I've ever worn my panties for was probably 4 months (I didn't grow much that year, maybe half an inch). I still haven't washed it, it's currently on top of my bed, along with my many, many other dirty clothes.
They used to be white with a butterfly on the front but now they're stained yellow and brown from me 1) not wiping properly (or at all)
2) standing up, pulling my panties as well mid-pee thinking im done, or doing the same thing but thinking that I've finished pooping but another piece comes out
3) just pee/pooping in them when I'm too lazy to get up
They're also really crusty (I think you can guess why). Sometimes I would walk around the house in those panties and a t-shirt.
I only stopped wearing them because I got some new panties from my Mom for my birthday.
But now that I think about it, I'm think I'm going to go put them on.