Sunday marked four decades of the Folsom Street Fair, what’s been billed as the world’s largest kink festival. Approximately 250,000 people were expected to attend the event, which takes place between 8th and 13th streets along Folsom. Although there were some plain-clothed attendees, most of the people traversing SoMa streets were sporting their finest BDSM looks, from assless chaps to dog masks. As a permitted street fair, the event is exempt from San Francisco city laws regarding public nudity, and quite a few people took advantage of that exemption, with some participating in public sex acts along the sidewalks.

Folsom Street itself had a revelrous party atmosphere in the sunny afternoon. The streets were closed to cars and filled with vendors selling a variety of playful apparel, ranging from the bottom-wear of Off Kilter Kilts to Geeky & Kinky Industries’ Mario and Luigi T-shirts (presumably not officially licensed by Nintendo).

The lines at the Double Scorpio poppers booth were nearly as long as the queues for the multiple public flogging stations. Spandex-wearing wrestlers grappled in a full-sized ring, complete with announcer and referee, while a group Twister game was taking place on another stage (“Grab a cheek… any cheek”).