The exact source of this gulu-gulu loop is unclear, since short vocal gurgles like this are usually recorded as throwaway meme audio rather than taken from a named show or film. Online it circulates mainly as a reaction-style drinking or gurgling effect: editors cut it under chugging clips, straw-slurp jokes, cartoon drowning gags, and exaggerated throat sounds in short videos. Its appeal is pure cartoon physics, a wet bubbling rhythm that reads instantly as gulping, even without any visible liquid. That simple readability keeps it useful across prank edits, anime-style reaction cuts, and silly soundboard chains.