When someone wipes their ass and it smears their shit all the way onto their nuts (usually can only happen with male)if it happens with a Female it would be called a Muddy Clam.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.