poop streaks
When feces rubs the inside of the toilet bowl and leaves marks. Easily remedied by multiple flushes.
Your mom left poop streaks in the toilet again!
poop streak
Having a light brown streak follow up from the bottom of your buttocks in your underwear towards your lower back. The brown streak is a remainer of feces.
I found my brother's underwear lying on the ground and I noticed it had poop streaks.