They have a word for everything, don’t they? This one made me laugh. 
Callipygian is an adjective that means “having well-shaped buttocks.”
The word comes from a type of statue of Aphrodite called Venus Kallipygos. According to the Online Etymology Dictionary, the Greek word kallipygos is a combination of “kallos ‘beauty’ + pyge ‘rump, buttocks.’”
When looking for an example sentence, I found an article in The Australian with a funny conclusion:
As for badonkadonk, an American coinage to describe curvaceous female buttocks (to do with the sound said buttocks might make when in motion), I just can’t see it replacing the perfectly formed callipygian. Those ancient Greeks left more than philosophical treatises to posteriority.
I have to agree. I just love sophisticated-sounding words with not-particularly-sophisticated meanings. And that’s why you should always look up the words you aren’t familiar with: you might have a good laugh!
“natiform” (to look like buttocks, without sugesting pulcratude)is a rarely utilized insult. you’ll need a ten pound Cambridge or Webster’s to prove it.
@jim: from my years of Latin classes, it’s pulchritude (sp)