Justin Bieber Flaunts His Bare Lily-Hued Ass on Instagram [PHOTO]

Justin Bieber is so edgy, what with his "swag," his tattoos, his weed -- he's basically becoming he male pop equivalent of Rihanna. Taking another page from her book, the newly single star has also taken to posting annoyingly revealing photos on Instagram.

The Reader's Digest version?

Justin Bieber's behind is on Instagram now. This is either a dream come true or a dry heave inducing nightmare depending on whether or not you're a 13-year-old girl.

Yesterday (Jan. 19) Bieber pulled down his pants, mooned his iPhone and put it online, just the way any classy, mature young man with legions of mouth-foaming adolescent fans would.

In the photo, Bieber rocks a black baseball cap (backwards, obvs, because he's so hood), aviators, a black tank, a smirk and far too little of his pants.

Thankfully, Bieber soon deleted the photo, but guess what's forever? Diamonds, Cher and screenshots.

Bieber's long-suffering and relatively fame-hungry manager, Scooter Braun, tweeted about the butt seen 'round the world: "As a prankster u have to respect another good prank. only makes sense. #crackdealer."

Crack is whack, kids. Especially when it's this white.