What is shit-moustache?

A shit moustache is the process of wiping ones finger between their sweaty ass cheeks and rubbing quickly and precisly under the moustache area

Before the stupid prick realised i had landed a beauty of a shit moustache right on his chops
mmmmmm finger licking good!!!!!

shit-moustache - meme gif

inserting one's finger deep into their anus, then proceeding to wipe it on an unsuspecting victims top lip.

whilst fingering his ringer, colin knew that it was time to get his aunty with the 'shit-moustache'

the filth monger got me with the shit-moustache