an act of sitting on the ground and playing in feces. Most commonly used as an insult.
Your mom took part in a farfidinkle at the county park!
You smell as if you took part in a farfidinkle!
Why don't you go over to the corner, defecate, and then have yourself a merry little farfidinkle!
Can also be used as a verb: You've been behaving so badly that you might as well just farfidink in front of everyone!