like, when you're taking a shit and after you wipe and flush your turd is dragged along the bottom of the bowl,leaving marks and sometimes primitive drawings.this is sometimes,but not always,discovered by the next user.also called extra credit.

Got the covid-19 vaccine

The beautiful designs and markings left on the inside of the toilet bowl after taking an extra-firm dump.
The firmness of the turd creates a "crayon effect".
Cave paintings will not wash away with flushing leaving but will deteriorate over time, leaving them for your friends and family to enjoy for days or weeks.

When a man engages in sexual intercourse with a girl without any form of protection. The man fails to 'pull out' in time, therefore leaving the female with 'cave paintings' inside of her nether regions.

a cave painting is when you are doing a girl doggy stle while she is on her period. And you pull out and draw something on her butt cheek with the blood.

An act of love that involves inserting the hand in the anal or vaginal cavity and writing your name or a pictorial on the inside wall with your fingers.

the markings left behind from a beastly turd after flushing it.