When you consider just how many people say they’re interested in the idea of group sex, it’s easy to see why this is an important issue to address. When I surveyed more than 4,000 Americans about their sexual fantasies for my book Tell Me What You Want, I found that group sex was something that almost everyone had fantasized about at one time or another. In fact, 95 percent of men and 87 percent of women reported multi-partner sex fantasies.

A sizable number of people have turned the fantasy of group sex into reality. According to the National Survey of Sexual Health and Behavior, a recent nationally representative study of the sexual practices of American adults, 1 in 5 men and 1 in 10 women said they’d had a threesome. In addition, 1 in 8 men and 1 in 16 women said they had been in an orgy.

So what are the implications of these extra partners for the issue of sexual consent? Intuitively, it’s tempting to think that the more people around, the less likely it is that someone will push limits and boundaries. In other words, there should be safety in numbers. Extra people should mean that someone will be more likely to step in when lines are crossed, right? Furthermore, those people could serve as potential witnesses if someone wanted to press charges later.

I’m not convinced that either of those things would necessarily happen, though, in light of a large body of research focused on helping behavior. I tackled this subject in a recent article published in the Archives of Sexual Behavior. For example, consider the phenomenon known as the bystander effect, which refers to the well-documented and counterintuitive finding that the more witnesses there are to a given crime, the less likely it is that victims will receive help. Why is that? Because of something called “diffusion of responsibility.” When there are more people around, each individual person feels less responsible for stepping up and helping out in an emergency.

There’s also the fact that when people are engaged in group sex, they might not even notice that a consent violation has occurred because their attention is pulled in a lot of different directions. I think it goes without saying that people don’t help others out unless they notice they’re in trouble. And during group sex, you may be in such a state of sensory overload that you fail to notice that someone in the group is communicating a lack of consent, especially if they’re doing so nonverbally.

Even if people notice a consent violation and do step in, this doesn’t necessarily mean that you’ll be able to count on them as witnesses later because group sex sometimes takes place in anonymous settings. Also, even if you do track the witnesses down, they may not want to come forward for fear of how admitting to being part of an orgy might impact their reputation. In our sex-negative culture, people—especially women—who participate in group sex tend to be judged harshly, being labeled as “promiscuous,” a “slut,” or worse.

This is not to suggest that group sex is necessarily rife with sexual assault or that it cannot be practiced safely and consensually. Let me be perfectly clear: That’s not what I’m saying at all. As I’ve found in my own research, people are more likely than not to say that acting on their group sex fantasies was a positive experience. My point is simply that navigating consent in a group poses a very different set of challenges than two-person sex.

The real question, then, is what we can do to help people who are turned on by the idea of group sex (and that appears to be most of us) to feel prepared when it comes to dealing with consent. For insight into this, I spoke with Dr. Kathryn Klement, an assistant professor of psychology at Bemidji State University and Dr. Kate Frank, an anthropologist at the University of Nevada, Las Vegas and author of the book Plays Well in Groups. Both have studied the dynamics of group sex environments.

For those new to group sex, Dr. Klement suggests that a good place to start is with a guidebook like The Ethical Slut, which has a chapter on group sex for beginners. After you get the lay of the land, you might consider visiting an established environment to play the role of voyeur before diving in or organizing your own group event. “In any environment, watching how others negotiate—how they say ‘yes’ and ‘no’—before attempting to do so oneself is probably one of the best strategies,” Dr. Frank says.

Most people don’t have a script for group sex, so observation can provide you with a mental framework that will help guide you in the future should you decide you want to give it a try. This will also give you a sense of the kinds of rules you should establish and the things you might need to take into account before you plan your own orgy. For example, will there be rules about alcohol and substance use to reduce the risk of someone being taken advantage of?

According to Dr. Klement, would-be group sex organizers would also do well to take a cue from the BDSM community. For example, you might consider establishing a common safeword as a clear way of revoking consent. In addition, in the BDSM scene, there’s a lot of negotiation in advance of sexual activity, and that’s something we probably want to promote in the context of group sex, too.

“Regardless of what type of rules there are, as long as partners are on the same page about what they want to do, and what they don’t want to do, people can enjoy themselves without worrying that someone will just ignorantly blow past a boundary,” Dr. Klement says.

You don’t just want to communicate at the start, though—keep it going. And if you’re worried that too much talking is going to kill the mood, Dr. Klement suggests reframing consent communication as a form of dirty talk: “What do you want your partner(s) to do to you? What do you want to do to them? Describing your ideal outcome for the event can be a form of foreplay.”

Check in periodically with your partner(s) as well. “This may sound really awkward to you if you’re not used to it, but I like to think that erring on the side of talking too much during sex is better than not paying attention to my partner and giving them a bad experience,” Dr. Klement says.

Make sure that participants feel empowered to revoke their consent if the need arises by letting them know they will be supported and that their boundaries will be respected. “We need to make people realize that they can and will have support if they need to say ‘no,’” Dr. Frank says. “If a person is empowered to say ‘no,’ then there is no harm done in asking or being asked, and no harm taken in being rejected.”

Participants need to know that there’s more than one way to say “no,” too. As Dr. Frank says, “perhaps organizers could encourage more discussion of the various ways that people can say ‘no’—for example, explicit verbal discouragement versus repositioning on a bed—because some people are more socially aware than others.”

While these guidelines may help you in navigating the world of group sex, there is something all of us can do to help make consent communication easier for everyone, regardless of whether we like to play in twos or in larger groups. We need to support comprehensive sex education—education that is focused on giving people the tools they need to communicate comfortably and confidently about sex and sexual desire.

“We need better sex education programming that addresses these issues,” Dr. Klement says. “I’m not advocating for roleplaying an orgy in 10th grade sex ed, but consent absolutely should not be considered an afterthought in [the] curriculum.  Having people able to talk openly about sexual topics when they’re younger means that they’re more likely to reach out for help and more likely to have a good time.” 

Justin Lehmiller, PhD is a social psychologist, Research Fellow at The Kinsey Institute, and author of the blog Sex and Psychology. He taught at Harvard University for several years and has written a textbook on human sexuality that is used in college classrooms around the world. His latest book is Tell Me What You Want: The Science of Sexual Desire and How It Can Help You Improve Your Sex Life. Follow him on Twitter @JustinLehmiller.