The phrase comes from Japanese, where 'Bikini nandaa!' roughly expresses excited discovery that someone is wearing a bikini. Its existing description references 'Passione 24 hours,' suggesting circulation through Japanese variety and online clip culture rather than a single confirmed anime scene. Shared on soundboards as 'bikininandaa,' the 1.6-second line spread as a compact reaction audio. Creators reuse it for swimwear reveals, summer edits, and exaggerated thirst or surprise moments, where the language barrier adds to the absurd, meme-like energy for international audiences.