Inside an unmarked warehouse in downtown San Francisco, a woman greets guests with a riding crop. She is not there to beat them, but to initiate them with a set of firm and binding rules. A chart posted on the wall reads:

• State your boundaries.
• Play safely and consensually.
• Have sensible safe sex practices.
• Respect our space and each other.
• Don’t linger unaccompanied in play spaces.
• Don’t cruise aggressively.
• Don’t get too intoxicated.
• Don’t take photographs.
• Don’t use your cellphone.
• Don’t gossip about what goes on here.

Using the riding crop as a pointer, she lays out the basics for guests entering Mission Control’s Kinky Salon, a monthly San Francisco sex party that dates back to 2003. “Kinky Salon is a global movement that promotes sexual liberation by hosting community gatherings where sex is integrated into the social fabric of the events,” reads the Kinky Salon manual, a guidebook to on how to safely construct a sexual play world where no one gets hurt. That means a strict set of boundaries.

The rules are the portal at Kinky Salon. After guests pass this point of initiation, they enter the warehouse—a two-story adult playground. Upstairs are performances, a DJ, and arts activities like portraiture and body painting. There are low-slung couches, people dancing, and a BYOB bar with a bartender who doles out your own liquor. It’s just a really good party. The play space where the actual group sex scene takes place is downstairs, tucked away in a corner.

"It’s not anonymous. And you’re not necessarily going to get laid. You can go and just hang out."

There are rules about consent, about how to solicit sex, how to negotiate for something different, how to say no. There are rules about protection, about fluid exchange, about staring, about drunkenness. The rules that dictate the boundaries of this seemingly boundariless space are the same rules that people often break in mainstream society: You have to ask before you touch. You can’t get extremely drunk. You have to honor when someone says “no.”

Rules and group sex have gone hand in hand for decades. The more risqué the sexual party, the tighter the guidelines, particularly in the BDSM world where partygoers consent to physical pain. “The space, people’s bodies are sacred,” Kinky Salon co-founder Polly Whittaker, aka Polly Superstar, recalls from her many years in the BDSM and fetish scene. “You do not talk while someone is having a scene, you don’t laugh, you don’t stare … They’ve created this incredibly strict structure because what they’re doing there is working through some really heavy shit and they need safety for that.”

“Kinky Salon is only one step away from the super strict rules of BDSM and there’s a reason for that,” Whittaker goes on, “which is that I think that women, particularly women in our culture, are not trained to state their boundaries.” The usual script that guides the more typical sexual encounter is replaced by a new one. In setting limits, edges, and rules of play, the possibilities for safely exploring new sexual horizons and thresholds become tangible.

Group sex parties run the gamut and are available for all types of people. The New York scene, which just last month opened a Kinky Salon, joining their list of hosted parties in Copenhagen, Austin, Berlin, Portland, New Orleans, and London, has its fair share of parties across the board. There are the parties just for single heterosexual couples, like Bowery Bliss, a weekly swingers party in lower Manhattan, for which “The term couple refers to a Male and Female. Two men are NOT considered a couple.” At others, like Submit in Brooklyn, a party for “women and trans folk” interested in all types of BDSM play, “There’s a shower, a boot black station, slings, a cross, bondage set-ups, beds, peep holes, and more.” One Leg Up requires their guests to leave together if they arrive together, and Chemistry, another Brooklyn scene, asks a series of questions to pre-screen their guests like, “What is your favorite non-sexual hobby?” or “What role does sexuality play in your life?” School of Sex’s Behind Closed Doors party requires an application and has four cardinal rules:

• Ladies make the rules
• No means no
• Men cannot approach women
• Members only

In constructing a separate world around non-monogamous sex, these parties are building small behind-the-scenes exits to dominant cultural expectations. The rules define the new sexual paradigm that guests willingly enter.

"Group sex offers the opportunity to challenge ourselves, to move our sexuality out into the open, banners flying."

Almost all of these parties feel the need to remind their guests that “No means No.” Consent, in this other world, is everything. There are parties for for S&M enthusiasts,cuddle parties, drag parties—all kinds of parties that offer a space for the open expression of sexuality in a new context each with their own set of rules. Kinky Salon itself is all-inclusive, special insofar as it offers a space for straight, gay, bi, in-between, or over-the-top people to gather in a safe, culture-centric space. Similar to clubs like Chemistry, which features a DJ and a dance floor, sex is not the only thing on the table—rather, it is the thing that defines the scene. Whereas some sex parties are just for getting laid, at Kinky Salon, sex isn’t a necessity. Some are there for the sex, which Whittaker calls “sport fucking,” while others are there to escape cultural norms and define a new, more liberating sexual universe that encompasses the full spectrum of their needs.

“Kinky Salon is different because it’s volunteer-run, it’s a community first and foremost, and you know you’re joining in as part of something,” explains Whittaker, author of the recent memoir, Polly Superstar: Sex Culture Revolutionary. “It’s not anonymous. And you’re not necessarily going to get laid. You can go and just have fun and hang out. You don’t have to have sex. In fact …most of them are coming for the community.” At Kinky Salon, guests abide by the PAL (“Pervy Activity Liaison”) system, meaning another adult must accompany them to help hold them accountable for their behavior. This means all guests are couples, triads, or chaperoned singles.

“We believe that it is a fundamentally radical political act to deprivatize sex,” write authorsDossie Easton and Janet Hardy in their famous book, The Ethical Slut: A Practical Guide to Polyamory, Open Relationships & Other Adventures. “Group sex offers the opportunity to challenge ourselves,” they write, “to move our sexuality out into the open, banners flying, with lots of support in getting past the fears and bashfulness and lots of friendly people to applaud your ecstasies.”