The phrase mne nuzhen seks is plain Russian, transliterated from Мне нужен секс, and its meaning is deliberately blunt. Online it circulates as a short standalone voice meme rather than a clip tied to a confirmed film, show or creator, so its popularity comes from the delivery and the translation reveal. Russian phrases often travel on soundboards for their sound alone, then spread further once non speakers learn what was said. That double reaction keeps this one in rotation for reaction edits and joke posts.