Bora has been everyday Brazilian Portuguese slang for let's go for decades, used for everything from leaving the house to starting a match. This stretched version spread as a WhatsApp audio in the late 2010s, with the file metadata dating this recording to February 2019. The humor comes from the exaggeration, taking a two syllable word people say constantly and stretching the final vowel far past normal speech. It stayed popular in Brazilian group chats as a quick hype reaction that needs no context or explanation to land.