When one's mustache begins to get to the persons head making him/her believe they are a complete bad-ass. Stash infections begin when one starts to believe they "cannot be f*cked with!"
That guy across the bar with the handle bar mustache is staring you down. If you say "hey" and and the man does not answer at all, leaving you with a stare, the man is suffering from stash infection.
by WIllie the Kid February 20, 2009