Sex parties and the rules that navigate their jurisdiction didn’t just spring up from thin air—they evolved to meet cultural needs for a shifting sexual world.

Terry Gould, author of The Lifestyle: A Look at the Erotic Rites of Swingers, writes about the origin of what she calls “a lifestyle.” “According to two doctors of sexology named Joan and Dwight Dixon, who have been in the lifestyle since the sixties and writing on sexuality in journals for two decades, the original spouse sharers were none other than World War II fighter pilots,” she explains. “It was the pilots and their wives who invented the term ‘key club,’ which was unknown in the 40s, became widely known in the 50s and 60s, and then was forgotten until the 1997 film about suburban swingers, The Ice Storm.”

Christopher Ryan, who wrote (with Cacilda Jetha) the popular Sex At Dawn: How We Mate, Why We Stray, and What it Means for Modern Relationships also traces the origin of our modern iteration of group sex parties to Air Force bases during World War II.

“As it turns out, the first ‘key parties’ weren’t about sexual pleasure so much as a response to the existential issues triggered by facing the highest death rates of any branch of the U.S. military during the war,” Ryan told me in an interview. “These guys had a one in three chance of dying during one of their missions in the Pacific. They got together and had sex parties, not as a way of getting more sex … but as a way of deepening the bonds that held their deeply interdependent community together. The tacit understanding was that the men who survived would look after the widows of those who didn’t.”

Whittaker thinks the origin of group sex practices can also be traced all the way back to pre-historic times. Citing Sex at Dawn and Timothy Taylor’s Prehistory of Sex: Four Million Years of Human Sexual Culture, she believes that sex was once a group activity for “cavemen,” and sexuality became private with the advent of agricultural society and property divides. “The most significant step towards the misogyny that we have in our culture now is the fact that because the patriarchal line is where the property is passed down, for a man to guarantee that his son is really his son, he has to control his wife’s sexuality,” Whittaker tells me. “It’s the only way. For a woman it’s easy, you know that baby is yours, but for a guy and if the guy is wanting to pass on his property, it’s not so easy.”

The group sex party, at least Whittaker’s iteration, is a space where the dominant dynamics—monogamy, heterosexuality, gender norms, etc.—can be sidestepped. Everyone is game and everyone is equal.

“Our hope is that everyone who attends a kinky salon experiences a shift in their consciousness,” the Kinky Salon website reads. And to achieve this, the party has the history of San Francisco’s sexual revolution on its heels.