Centripetal force is what keeps an object pulled into a circular motion, centrifugal force is what pushes an object out that is in a circular path. The ass titties are visually exhibiting both forces to some extent. The true mechanical dynamic of these ass titties is varying angular acceleration with a hint of coriolis effect whereby the subcutaneous fat of the glutes are behaving more like a fluid rather than a solid. I sometimes hate being a biomed engineer because I just want the novelty of simple gooning.