The clip built its audience on soundboards and short-form video where tiny anime voice lines are reused as instant reactions. Onii-chan comes from Japanese family language and is widely recognised through anime and manga culture, where younger characters use it with exaggerated affection. This Sergio version is shared less as dialogue and more as a punchline, pasted over gaming clips, chat recordings and edits when someone wants a moment to feel suddenly cute, needy or teasing without adding any longer explanation or setup.