Não me diga is a common Brazilian Portuguese expression meaning do not tell me, similar to you do not say in English. As a short meme audio it spread through WhatsApp groups, TikTok edits and soundboards, where its brevity makes it easy to reuse. Creators pair it with reaction faces and obvious statements rather than genuine surprises. It belongs to the same family of quick reaction clips as the bruh sound, and remains popular because the phrase is understood instantly even outside Portuguese speaking audiences.