Rou bian qi is the Mandarin reading of characters that spell niku benki in Japanese, a term long circulated in adult doujinshi, eroge and translated hentai forums before moving into general meme slang. As Chinese and Japanese fandoms overlapped on video and chat platforms, the phrase was clipped, reposted and turned into a standalone reaction sound detached from any single scene. Its continued use comes from that portability, as listeners who recognise the slang get the joke instantly while others hear only an abrupt, odd foreign phrase.