Inevitably, you notice her legs first. Photoshop-smooth, they don’t stop until they hit shirt. The original tagline didn’t bother to compete. “Friendship has its benefits,” it shrugged, winking and broad enough to be made by a bawdy aunt, a corner-store clerk, a talking animal. The second advertisements read differently: “Can sex friends stay best friends?” An unremarkable tagline for what promised to be an unremarkable movie—but someone has used this text, of all texts, to coin a phrase. As a lexical unit, sex friends barely exists. A two-episode anime called Sexfriend, a Japanese “pink” movie called Sex Friend Nurezakari, and a handful of song lyrics. Beyond that, nothing. “Sex friends” is here because it near-rhymes with “best friends.” It is very, very hard not to want it to read “fuck buddies,” which is something that people actually say, and which is horrible. So what if the invention is a mishap of sloganeering? Why not this guileless, unclunky contender? In the time it takes for the bus ad to roll out of your vision, “sex friends” goes from jarring to snug, filling in what turned out to be an ugly little cavity in our language.