A flag design on swimwear, or similar garment, apparently to make the outfit even sexier, or at least very distinctive. For some reason, the U.S. flag seems to be the most common, but it's not the only one. It often shows up in advertising, particularly if being worn by a Hood Ornament Hottie. Some people consider this disrespectful to these flags (and Brazil actually bans its flag on swimsuits), while other people don't seem to mind, as shown by the popularity of this kind of suit. A Sub-Trope of Wearing a Flag on Your Head. Examples of Flag Bikini include: