The additional call of nature - very similar to the first - that lures you back into the toilet, even though you're pretty sure you've just moved your bowels satisfactorily.
Sid: I'd better go, Hank. I need to take a dump again.
Hank: But I thought you went before you came out.
Sid: I did, but I think it's a de ja poo. It feels exactly the same.