A "sling bikini," also known as a "slingshot swimsuit," is actually a type of one-piece swimsuit that stretches from the crotch, separates to cover the nipples, reaches to the shoulders and across the back. It can be best described as a thong that goes over the shoulders, providing minimal coverage to the wearer.

(Copied from Danbooru)

Updated by vistigris about 15 years ago