When you hold your shit in for so long that your body compacts it into the only known geological formation which can cut through a diamond. It is theorized that very center of the sun contains a small core of poop rock.
I once ate three square meals a day and yet did not take a crap for an entire week. That totals up to 21 meals without shitting. When I finally did, I excreted a perfect diamond. I have yet to attain a Poop Rock.
pooprock (v) a pooprock is a poop that is so big, hard, and lumpy that it hurts really bad and your face turns red; The worst part is that sometimes it turns sideways and creates a little bridge over the toilet hole and it won't flush so you need to some how break it up
Dude, i had a monster pooprock last night and aaron had to break it with a plunger because it bridged on me.