Summer Bikini Beach Buttock

uropygial in ornithology mean, situated on, belonging to, the uropygium, i.e. the rump of a bird
- "bubble butt" has at least two connotations, which are at odds with each other: either a small, round and firm pair of buttocks resembling a pair of soap bubbles next to each other, or a large rear end, seemingly about to burst from the strain. In both cases, the term implies an appealing shapeliness about the buttocks.