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Welcome to “It’s Complicated,” a week of stories on the sometimes frustrating, sometimes confusing, always engrossing subject of modern relationships.

Threesomes are one of life’s greatest pleasures, ranking alongside glacially cold seltzer, seeing a baby skunk in the wild, and the poetry of Guillaume Apollinaire. That good.

There are many groupings, roles, and shapes in which you can enjoy them: I have been the special guest star as well as part of the host couple plenty of times, in differently gendered lineups, and left each bizarre love triangle with a song in my heart and exhausted mouth muscles. Group sex is like reading an Apollinaire poem about a baby skunk WHILE guzzling a crispy Schweppes. That good.

A threesome with three breathing beings, two of whom have been involved for longer than just that night, usually has to be artfully assembled. Group sex, when it involves a long-term couple, can veer into gruesomeness if you’re dealing with delicate personalities — which is to say, “personalities.”

The biggest challenge of menage‑a‑triangles for those in relationships is the fact that you have to account for and manage not only your and one other partner’s happiness, which is strenuous enough on its own, but those of another person forming all-new angles in this shape. Each person involved is CAUTION — FRAGILE, because threesomes can feel like ego wrecking balls even if they’re handled with the softest of kid gloves.

When they aren’t? You know how it’s rude to insert sidebars into conversations with three or more people that you know only you and one other person in the group will get? Imagine that same ill-mannered behavior, except naked. Nobody likes to feel neglected, or extrapolate that into butchered self-esteem. I am happy to say I’ve never experienced that, but that is, in large part, because I would never become involved in a threesome that I foresaw was an emotional demolition derby disguised as the kind of agreeable fuckfest that I wondered about from pornography.

Asking the person to whom you are committed to have a threesome with you might feel daunting if you’re monogamous with them. This doesn’t mean it is impossible, or that they’ll shoot you down out of hand.

If you’re uncertain whether your person will respond favorably to a three-part harmony, do some detective work. Just maybe don’t do it by saying, “Hey! You know your friend Dan from the radio show with the graceful hands and shag-carpet chest hair? I want to lobotomize him via fucking his brains out. Wanna join in, person I love?”

The two predominant fears when it comes to group sex are jealousy and exclusion. Once you’ve worked out that each party is willing, take care of the following and you’ve got very little to be afraid of:

In couples, the suggester lets the suggestee pick the third — and, without a couple’s encouragement, a third probably shouldn’t ask at all. If you’re asking for a threesome, your main collaborator gets to pick the featured guest. Even if your girlfriend is giving you one “for your birthday,” which is kind of a harsh toke from the outset — does she want to do it, or is she feeling pressured into making you happy “this one time” by doing something she’s uncomfortable with? It could easily be the opposite: She wants to do it, but is self-conscious about that fact, so she’s got to wrap it in a bow — much like when I get loved ones expensive caramels as gifts because I know they’ll open and eat them WITH me.

Pointing out an object of your affections can get someone’s guard up because it invites instantaneous self-comparison, which is something you want to AVOID as much as possible, for your sake and your triangle’s. It’s going to be difficult enough when you’re sizing up a person’s naked flesh as measured against your own, or when your person is, so don’t invite that beauty contest as you broach the idea to begin with. Suggesting a fuck-pal could also lead your person to believe you’ve been harboring a sexual or romantic YEARNING for your intended, which is … not that cool to think about, if you’ve been actively boning and/or adoring someone who, the whole time, has been wanting to bone/adore someone other than you. Not that there’s anything wrong with wanting to fuck/love two or more people at once! There isn’t. But don’t bring your main person into it unless they want that, don’t fuck/love around on them if you’re monogamous, and if you find yourself YEARNING instead of being present in your current relationship, open or not: Consider ending it.

Do not assume a person wants to have a threesome with you because they’ve done so with others. That behavior roundly munches sewage … but I also get its incentive. If a person has intimated they love the sonorous musicality that often comes with playin’ the triangle, a complex, beautiful genre their audience has long considered beyond the reaches of its talent, it might be tempting to ask them for lessons. That’s fine! The pivotal point of that sentence, though, is the word “ask.” Would you demand that a known triangle solo artist whip out their wand and give the virtuoso performance of a lifetime with nary an inkling’s notice? No, you have never done that — you’re not that rude.

Don’t expect a threesome of someone solely because you know, or are guessing, that they have had one before. Don’t expect a threesome of someone even if you’ve had it with the same configuration of people before! People’s angles are less rigid than those found in geometry. You are not treating that person as a person, which is the most essential part of the approach to group sex in general: No one is anyone’s sexy attache. Everyone has the right to say what their limitations are not only during, but before.

In an intergender couple, the person of the same identity (if there is one) as the person being asked does the actual asking. Sorry: This suggestion feels archaic. But there’s a lot to be said for considering the perspectives and experiences of your target, then deploying whichever member of the home team might relate to them most closely. I like having one person act as the amanuensis and point of communication for both others, and that person should be the one whom the other two trust, collectively, the most — across the interpersonal board, and as applied singularly to this situation.

This can speak to a diffuse range of considerations: Maybe the third has known one of the players in question since goon-times, or perhaps shares a CSA with another. Most commonly, though, this is going to boil down to good old-fashioned gender essentialism. When I’m closer with the male figure of an equation, I am persuaded that a situation is cool, on the level, and a potentially entertaining passage of a Thursday evening when the female arm of a twosome reaches out to me. Since we’re going to be, for a time, body doubles playing an at least somewhat similar role, no matter how disparate our interpretations of it, I want to know that we’re countrywomen — that we’re each heading into the threesome knowing what the other’s deal is, and how to make her feel good and psychically protected. If you are all three of diverse, or identical, genders, go ahead and dispatch the person who speaks to them most effortlessly about how wild the ninth grade was, or this week’s CSA selection of root vegetables, or whatever point of connection you’ve decided is basis enough for a bout of group sex. (Both topics have worked fine for me in the past.)

Do it with ANOTHER couple. Having sex with another allied force means that everyone is approaching the four-way with just as much to lose!! Hee, I kid — look at it the other way, and you are viewing it correctly. Empathy will come more easily to a couple in your same romantic situation, and close friends might be more considerate of one another’s feelings and careful not to homewreck your shit.

Three strangers or loose acquaintances are least messy after the fact. I love a threesome comprising three randeaux. There are no lingering love-politics about which to have Serious Check-Ins (aka the WORST part of relationships, even though I know it’s, yes, necessary and healthy — hard conversations are the vegetables of romance). Each and all parties are equal, and equally ready to party.

In any case: GET KINDA DRUNK. But not too drunk, doye.

A note on asking a previously platonic friend to take part in a threesome: You’re always going to face some risk of offending someone when you make a pass at them. A unilateral truth: That risk winnows when you hint at your interest and gauge if the other person reciprocates it with genuine curiosity and levelheadedness (rather than going, “Oh, he smiled back — SHAGADELIC”).

If they’re freaked out? They have the right to be surprised, but they also have to respect your sexual realité as much as you do theirs, so end the conversation if they decide that a cool way to respond is by insulting or berating you. I have never had that happen, and I hope you don’t either!

A note to special guest stars: The key to nailing your walk‑on role in someone else’s relationship: It’s best not to try and steal the show here. While this is a fun and light evening for YOU, people with whom you’re sleeping are going to maintain joint custody over this memory for the rest of the time they’re magnetized to each other. While it’s up to them how they approach your encounter — there’s no way to control other people’s feelings — you have some responsibility to contribute to its emotional tenor. How are these two treating each other? Are they looking at each other with great devotion and intensity? Don’t try to hop in on that. I’m thinking of the words “equal” and “equitable.” Wreathe both parties with affection and attention equally: Make all parties feel sexy, included, and accounted for. Menagin’ is the best — have fun.

Excerpted from Action: A Book About Sex published by Grand Central Publishing. © 2016 by Amy Rose Spiegel. You can follow her on Twitter and Instagram.