The whaletail thong is a specific style of thong. Generally speaking, the thong offers modest coverage in the front and has thin straps as sides. The back is usually a thin wedge of fabric that connects to the side straps and nothing covers the cheeks. They're becoming quite popular as a panty and bikini style. Why would any one wear something like this? Because they're actually comfortable and, more importantly, they eliminate any visible panty lines that can show when you're wearing close-fitting pants or skirts. No bumps or bunching or unsightly lines! They're perfect for both every day wear and special occasions and really, once you see how great they are it's likely you won't go back to your regular panties.
So then, what is this whaletail thong version you ask? Well, image the tail of a whale. Or better yet, take a look at the picture below. On a whaletail thong, the back of the thong has the same gradual taper from the center wedge of fabric to the sides as the shape of the tail of a whale. Aptly named, right? There's no super cool design feature to them or a reason or occasion to wear one style over the other – it's just about the aesthetics. If you really want to get down into the details, the whaletail thong uses a bit more fabric than the average thong in order to create the sleek telltale shape. Other than that, the two styles are virtually the same and, depending on who you ask, some women may claim that the whaletail thong has a much sexier overall look. Again, it's all about aesthetic appeal.