It is a party mainly for people to get drunk and have sex. Usually random people show up and the party is often kept quiet from the public. Many people who are in relationships show up at swinger parties to 'swing' or enjoy a different style of sex. Orgies and group sex is very common at swing parties too.

when you've done something so cringe you can't stop replaying it in your head and it stops you from getting on with your every day life