Jennifer Lopez and Iggy Azalea -- LIVE Booty Ain't Always the Best Booty

After Iggy Azalea and J.Lo broke down "Booty" live on the American Music Awards stage ... it was time for Iggy's mentor T.I. to weigh in on that highly anticipated ass carnival.

Two thumbs up? For the dancing, not their ... well ... y'know what -- let's just review the video.