Warning: explicit content
It's a common myth that sex parties and orgies are the same thing.
Indeed, both can involve sex with multiple people, but sex parties are usually not a physical free-for-all. While an orgy is probably more informal, a sex party is organised and proper ones come with clear sets of rules.
Here's what you need to know:
Are sex parties creepy?
You might encounter people that make you uncomfortable at sex parties, perhaps because you're not attracted to them but they are to you. However, your mere presence at such a party isn't an invite for people to touch you. General social hook-up etiquette applies, which means lots of talking, shared eye contact, and body language will precede sexual interest.
Generally, those who go to a sex party are all up for a similar experience and have mutual fetishes. If you think it's creepy for somebody else to watch you have sex, these parties are not right for you. Some people (particularly couples) will be exploring their sexuality vicariously through others at a sex party, and taking memories to their own bedroom with them.
Where are they held?
Sex parties held at bars, clubs or other venues are usually more about meeting like minded people than actually engaging in sex.
In fact, most of these parties in publicly-accessible venues tend to be a form of "play" party: attendants are not pre-approved, people wear underwear or other minimal clothing, and any sexual activity is often limited to another space and probably won't be penetrative. Such play parties are a lot more manageable for beginners.
Sex parties at private houses can be a more hardcore affair. Guests are pre-approved by the host – normally you need someone in that scene to vouch for your character. A well-run sex party should have very strict rules about safety and consent, and violations are taken seriously. Condoms and lubricant should be liberally available. Sometimes there's a theme (not surprisingly, Ancient Greece and Rome are popular in many scenes) and if you're not dressed to it, you'll probably feel out of place.
Must you go with a partner?
Most people feel safest when sex party attendance is a kink they share with their partner; they're willing to explore together. Some people will only have intercourse with the person they came to the party with – the enjoyment comes from the exhibitionism side of things – not the new people they meet.
Others may want to meet new people and make physical connections with them while their partners observe, some may want to partner-swap, others may be keen on group sex. Don't forget, too, people attend sex parties just as voyeurs. For many people the joy is not even in participation.
What can you expect?
Most sex parties have a place to check your clothes and belongings at the door, and many people keep shoes on. Like any party it will be alcohol-fuelled, and some sex party scenes have drug cultures so that's something you need to be aware of too.
Guests will be talkative and flirty and everybody tries to leave their judgement at the door. Unless you're going to a niche sex party, all shapes, sizes, genders, ethnicities, and sexualities may be represented. Having a perfect body is not a requirement – sex parties aren't just for pretty people – but expect to encounter mostly body-positive folks.
As for actual sexual encounters, meeting people is more like meeting in a bar, and less like jumping straight into a California king bed with someone you've never spoken to.
Guests usually try to have genuine connections with each other and they escalate from there. Nobody is having sex with someone they don't want to (as noted, consent is key). Similar to any bar-like situation, you can politely turn down someone's advance and it should be respected.