Bill and Ted are the laid-back, time-travelling best friends at the centre of the Bill and Ted comedy films, known for their surfer slang, air guitar and relentlessly optimistic outlook. The line 69, dudes fits that persona perfectly, turning a number with an obvious double meaning into a cheerful, innocent-sounding greeting between friends. As a short soundboard clip, it has circulated among fans and meme editors who recognise the characters instantly, even without seeing the scene. Its staying power comes from that combination of nostalgia, brevity and a joke that needs no explanation.