Mucky bum is derived from the ol' salty eye but it actually happens when you've tried to push out a fart that wasn't really a fart afterall thus creating the mucky ooze that starts the ol' salty eye process.
by brentlyexperience August 31, 2008
Mucky bum is the result of passing copious amounts of excrement and having it stick to unusually long anal hair.
by RideshareLingo November 30, 2019