On the Internet you can often find erotic advertisements with orgies, sex parties and other forms of group sex. Look for a good orgy and sign up.
OK, so now what? You've done it. Now that you've found a party, picked the right outfit and date, and avoided fake make-up, it's time to actually go to an orgy. By the way, don't eat too much on the big day. Farting in a bubble bath during sex is generally not recommended. I'm sure there are parties where it's all about farting, but I won't find them for you.
Find out what the rules are and stick to them. As mentioned above, many of the rules at sex parties are about what men can and can't do. These rules are there for a reason (women's safety), and people of either sex should abide by them. Other important things to keep in mind are: Keep your phone in your pocket. No one wants to end up on a porn site. And if the rules say you can't do drugs, don't do them. Only have safe sex, and only with permission. A room full of naked people is not an invitation to take what you can get. If you want to touch someone, ask. If you want to see them, ask. If you want to do a 69 with someone in front of their husband while another couple hits on you, ask politely. If someone doesn't feel like it any more, respect that and stop immediately. Our manners distinguish us from animals, and in orgies, that's pretty much the only difference.
If you've just arrived, have a drink and mingle with the guests. It's not like everyone hangs up their coats and immediately starts working their tongues. Most parties have a lounge area where everyone wears (some) clothes, drinks, dances and flirts like in a normal bar. Stay there first and make eye contact with some strangers. After you have had your first drink, try to talk to someone. Remember that this is a room where everyone expects to make contact with a stranger. So it's like any other club you've been to before.
A few drinks can help calm the nerves and get the love juices flowing (bah, sorry), but don't try to drink yourself to death. People aren't here to break up, they're here to fuck. If you're still a bit shy, try a kiss first to break the ice. It's wise to move more gradually for several reasons. As with drinking, you need to build up the pace gradually. You don't want to be exhausted or sweaty and come home in the middle of the night. It's also okay to be present and not have sex with anyone. These things are there to find out what you like. You might find that it's not your kind of party, that your kind of sex partner isn't there, or that you just find it more relaxing to hang out. That's all fine.
Check out That's it. You're in the taxi on the way home, and the orgy part of your experiment is over. How did it go? What did you like and what didn't you like? What was the best part? What would you do differently next time? Would you do it again? If so, where? Take time to process the event. If you went with your partner, talk about the evening together. You may not like it at all, or it may make you so horny that you go straight home. Above all, you have to be willing to broaden your sexual horizons and try something new. Whether you want more group sex or not, you should be glad you came.