When the mound of poop is so big that it tries to ‘return home’ by going back into your anus.
Don’t forget to flush before the Prodigal Poop returns home.
A large poop in a low-flow toilet piles up until it reaches your butthole— thus returning from whence it came. Therefore it is called The Prodigal Poop.
I should have flushed half way through this morning. That Texas Tube Snake turned into a real Prodigal Poop.