present participle. Tastefully pecking upon poo-poo.
Related terms: poo-eating, poo-chomping, poo-gobbling, poo-sucking, poo-licking, poo-munching, poo-ingesting, poo-snacking.
Real citation: "you poo-nibbling cricketfucker."
(Sept. 11. 2004, http://www.madnesstemple.com/forum/7782)
Made-up citation: "Although it is yucko and wrong for humans, poo-nibbling is both nutritious and socially-acceptable for many small mammals, including bunnies--even the Easter bunny if you must know."