park a darkie

To defecate, do a poo, to go to the toilet, number 2
-to sit upon the toilet seat and lay a good healthy brown faecal log into the bowl.

Parked a darkie, parking a darkie
also spelled darky

Houseboy: "Would you like a massage now, George?
Clooney: "Not now, I'm about to go park a darkie."