An ‘ebonic’ expression for an extremely curvaceous female behind. Women who possess this feature usually have a small waist that violently explodes into a round and juicy posterior (e.g., 34c, 24, 38). Other characteristics would be moderately wide hips and a large amount of booty cleavage (i.e, depth of butt-crack).
While a badunkadunk can simply mean an amazing, nice, big booty... if specificity is needed a badunkadunk means an amazing, nice, big black booty while a wadunkadunk means an amazing, nice, big white booty. Very rare a few years ago, the numbers of wadunkadunks are increasing worldwide, and it's for the best.
Tyrese: "Ohhhhh maaaan that Stephanie has got one great wadunkadunk"
Jim: "Word nigga, who says white girlsdon't got it?"