When a male is banging another in the poo poo hole, then pulls out and marks his lover with his feces coated dick on the upper lip in a pattern not too dissimilar from the mustache sported by Adolf Hitler.
That skinhead is such a Nazi lover, he gave his bitch a Hitler stache.
A style of wearing one's pubic hair in which the genetals are completely shaven except for a small square patch of pubic hair directly above the genetals; Thus bearing a resemblance to how Adolf Hitler styled his mustache.
Boy #1: "Did you score last night?"
Boy #2: "Yes"
Boy #1: "Was she clean shaven?"
Boy #2: "No, she had a Hitlerstache"