After taking a large poop, the act of not wiping and allowing the poop to dry and get crusty, followed by the sensation of having the top of a pineapple in your asshole is known as pineapple butt.
Man, Chipotle was out of toilet paper. When I got home, I had a bad case of pineapple butt
I started to bleed from wiping but still had shit to remove. Two hours later, I had wicked Pineapple Butt.