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Excess poundage in the buns (booty or buttox) resulting from half-assed dieting and half-assed exercising.

"Bundage" is a portmanteau from the combined words of "poundage" and "buns."
"In his delusional world of doing everything half-assed, he believed his workouts and protein dieting would give him the body of Adonis but instead all he did was up his bundage."
by cooperage April 02, 2012