When you take a dump, and the poo has slid into the shadows of the toilet bowl, and cannot be seen. There's also nothing on the toilet paper when you wipe.
I just came back from the shitter, and I'll be damned if it wasn't a "poodini"...it was quite an illusion, cuz I coulda sworn a little turd slid out!
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.