I’m a professional prostitute. Personally, I’ve had at least 15 to 20 threesomes with different couples as well as my own boyfriends, plus one drunken gang-bang.

In short, I’m quite experienced with the more popular version of threesomes (two girls, one guy), which gives me ample expertise on sharing with you, the reader, the 10 major rules you MUST abide by if you’re going to have a successful threesome:

1. If your partner is pressuring you (either aggressively or passive-aggressively) to have a threesome, don’t feel obligated out of fear they’ll leave you.

To draw a comparison, it’s unlikely I’ll ever be able to have anal sex with a partner; I’ve tried several times and was practically doubled over in pain. If your unwillingness to try a threesome (or anal or whatever) is a deal-breaker, they don’t deserve you and should be kicked to the curb anyway for disrespecting your boundaries.

2. Agree on boundaries beforehand.

Is the other woman allowed to give him oral? If so, is she obligated to use a condom or dental dam? Is he allowed to penetrate her? How much lesbo action is the man looking for? There’s a spectrum from just kissing and rubbing to girl-on-girl oral and double-ended dildos. If you’re the third person, be sure to establish boundaries before starting (I usually consult the woman).

3. Set realistic expectations.

Just how much are you two comfortable doing with this other person? Is one of you getting the short end of the stick? Is your partner expecting too much out of it because they’re getting carried away with the fantasy? If it’s your first time, acknowledge that cold feet could occur (a glass of wine might help break the ice).

Usually, the couples I’ve seen discuss ahead of time whether it’s going to be “all about him” (let’s say as a birthday present) or “all about her” (she’s bi and he wants to let her play with that side of herself without cheating). Of course, it’s not always about one person or the other, either, in which case both people get something equal out of the experience.

4. Consider the emotional and physical ramifications.

Threesomes are a great way to spice it up and enjoy sexual acts with someone outside your partnership without cheating. However, what if one or both of you gets jealous? What if one of you ends up seeing the third person again but alone and in secret? This happens all the time. (Trust me, I know.) And it’s usually the man who gets a bit addicted and wants to do 1-on-1s on the side.

5. Make sure the third person has some idea of the tone because they aren’t as familiar with your sexual preferences.

Are you going for soft and sensual? Rough and tumble? Amateur porn crazy? The other person deserves to know, especially if you want to play rough, role-play or have a dominant/submissive tone of degradation.

When a couple I saw as clients were talking dirty to each other, they’d say, “You like watching me f*ck this whore?” It hurt my feelings to the point I almost hit the time-out button, but I let it go, assuming it was heat of the moment dirty talk meant more to turn themselves on rather than degrade me.

(Plus, I am a whore! I just command respect and won’t see — or re-see — clients if they are genuinely disrespectful.)

6. If you suspect your partner is secretly bi or gay, this could be a good litmus test.

Just think about how you will handle it if this truth comes out.

7. If you are the man, make DAMN sure you attend to your woman during the threesome.

Don’t over-emphasize and overly-focus on the other person. Always remind your lady via eye contact, verbal validations and physical actions that she’s your #1 and this isn’t going to threaten your relationship.

If she’s comfortable and turned on enough to watch you bang someone else or focus on the third person more, you will likely know this going in; if not, assume she’s your primary focus. Same goes for gender reversal.

8. Have a dignified and realistic parting of ways.

Don’t do the fake “let’s do this again!” bad first date cop-out. Try and end on a high note, but also be fair and realistic to each another in a way that all parties feel respected.

If the chemistry is good, definitely entertain the thought of doing it again, and if the chemistry is off (or you want to uphold your boundary as a couple not looking for someone getting clingy), it might be best to make clear it was a one time only episode.

9. Don’t get too addicted and carried away once you’ve popped your threesome cherry for the first time as a couple.

Discuss as a couple how often you want to have threesomes and whether you want the same person to join or whether you want to mix it up. Establish rules about whether each of you are allowed to see the third party on your own and, if so, whether the boundary is a friendly coffee (fully clothed) or some sexual activity within agreed upon boundaries.

10. Practice safe sex.

This should be a no-brainer, but even if the third in your threesome is a trusted friend, either use condoms and other protection or agree to get rapid testing prior to the encounter to rule out all STDs. Never assume someone’s clean. Many people selfishly claim to be STD-free to avoid condom use and other precautions that can diminish the pleasure level.

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This post originally appeared at YourTango.