An all around insult. It can be used in any situation where a person is or has done somethingparticularly stupid. However it is definitely not something to take offensively, because it is not the kind of word where you could take offense, such as "idiot" or "retard".
To dunkle someone, is to dip your balls in tea (preferably Earl Gray) and then drip the liquid into a recipients mouth. Immediately following this, the person who dipped their balls in the tea should make rough sex to an un-buttered english muffin.
The act of emitting dookie, dung, or poop into someone elses anus. They then jettison this fecal matter, along with some of their own back into your anus. It is not sexual! It is recreational! Feel free to 'dunkle' your grandma, uncle, or baby nephew!