There is a significant difference between sex and assault, but often the two can cross lines. The only time sex and assault should ever cross or blur the lines is when it is consensual.
I have discussed this before; consent is always necessary. Even if it is with a partner, you are in a relationship with, regardless of how long you have been dating. You always need to ensure your partner wants to have sex and that they are of the right mind to consent to all types of play, it must be consensual, always!
Unfortunately, kink and abuse are more common than most would believe, and many people put up with the abuse because they have been led to believe that it is part of the dynamic.
Sex parties aren’t overdressed gang bangs where when you step in, and you get accosted by horny people who just want to fuck you. Some sex parties might have a theme, and these might be glamorous and over the top, but it is not always like that.