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when an obese person decides to take off their clothing and swim in a body of water. not recommended for skinny people's sake.
Man, I was taking a nice stroll around the lake when I saw Bernice and Alfred chubby dunking together. that shit should be illegal.
by michy poo June 10, 2008
Adj. It is the equivalent of a fat person skinny dipping
John: Do I see a whale in the ocean?

Henry: That's not a whale. That's just a fat guy Chubby Dunking
by Slade the vigorous masturbator April 04, 2014