The phrase combines two pieces of Brazilian Portuguese slang: baiano, meaning a person from Bahia, and mijão, a crude, joking word for someone who pees a lot. As a short soundboard clip it circulates mainly through Brazilian meme pages, WhatsApp groups and short video edits, where regional nicknames are often turned into exaggerated insults for comic effect. Its popularity comes from that shared slang rather than a single known scene or recording, and it survives because the three second shout is easy to recognise, share and reuse out of context.