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.
ex.2"whoa,that was a bad turd.greasy but tight.*looks in the bowl*EWWW!!fuckin gross.
He wanted to remember me forever so I cave painted my initials in his ass.