When you have poop on your upper lip like a mustache. You can have many types of poopstaches in the form of a traditional mustache- like pinchers, goatee, soul patch, etc.

A thin, weak, fine collection of hairs on the upper lip that is noticible but not technically thick enough to be considered a real moustache. They are usually found on pubescent boys aged 13 to 16 whose moms won't buy them razors.