Cristiano Ronaldo created the Siuuu celebration during his time at Real Madrid, combining a jump, turn and shout of si, the Portuguese and Spanish word for yes. It became his trademark after goals for Real Madrid, Juventus, Manchester United and Portugal, and fans began chanting it in stadiums worldwide. Clips of the shout spread widely on YouTube, TikTok and football edits in the late 2010s and early 2020s, turning a stadium celebration into a universal online sound for success, confidence and playful bragging.