The phrase comes from Backpack Kid, the young dancer whose floss dance became a huge viral trend after clips of him performing it spread across social media. His confident, repetitive chant matched the simple arm movement perfectly, making the sound easy to reuse in short videos, memes and dance challenges. As the floss moved from playgrounds to games and pop culture, the clip kept circulating as shorthand for showing off, and creators still use it when they want an instantly recognisable dance reference.