When I was drinking at home in a mixed-gender share house where there was a rule that "Sex is prohibited in the share house!", I heard a rumor that one of the residents had broken the rule! "I can't forgive that!" Men and women get drunk and start flirting, saying, "Then we should too!". As long as we don't get caught, it's OK, so we start doing it in various places such as the room, the bath, and the toilet, but if that's not enough, we switch partners, share dicks and pussies, and have a huge orgy with men and women all mixed together!