Derived from the standard Harnish, a crusty Harnish is when someone with a moustache is fapping so fervently that he spunks so hard it splooshes into his moustache. In the heat of the fap session the jizz goes unnoticed for the rest of the night until his mother tucks him into bed with a kiss.

Adj. Something that is expected to have a long lifespan by virtue of having existed for a long time, based on the lindy effect, named for the New York restaurant Lindy's, coined by Albert Goldman and popularized by Nassim Taleb.