Nightclub bouncers/doormen who chuck out drunks and trouble causers OR muscle bound men who support prison officers in 'calming' down bad behaving prisoners.
Prison officer: I got spat at while passing cell 37 so I pressed my button and the hairy arse brigade came to my aide.
Alternate spelling, "Arse-hair demon": An extremely small, gnome-like creature, with powers of invisibility, who sneaks up on unwary victims, and gives their perianal hair a sharp tug, causing them to shriek, and/or leap skyward, for no outwardly perceptible reason.
Ariel and Deanna were enjoying high tea with the Queen, when HRH suddenly gave a sharp yelp, and leapt from her seat. Royal Guardsmen rushed towards the table, but Her Majesty waved them off, stating, "Bugger off, ya sods, 'twas merely a wee arse hair demon, ticklin' me hindparts."
Little invisible monster that grabs the hair on a guy's arse when shagging. Pulls the hair back and forth as hard as possible, resulting in the guy increasing his stroke rate to previously unimaginable speed.
Girl 1: "So, you got it on with Andy last night huh? How was it?"
Girl 2: "Andy was such a considerate lover until the point that the arse hair demon entered the room. Then he just pounded the shit out of me."
Introduced by the third Earl of Spender in the early 1900's. If you have a hair across your arse you are in a fould mood about something. AS if something is interfeering with your shit.