Glossary
Train
Train, or "running a train," is slang for a group sexual activity in which multiple partners take turns having sex with one person one after another.
Train, also phrased as "running a train," is a slang term for a form of group sex in which several partners take turns having sex with one person in sequence. The word shows up across gay male, queer, and broader sexual slang, usually in the context of group play, sex parties, or hookup settings. Like any sexual activity, it depends entirely on the clear, enthusiastic, ongoing consent of everyone involved, along with communication about boundaries and safer-sex practices. The term is casual and explicit rather than clinical, and it carries no single fixed meaning beyond the basic idea of taking turns.