Loved it!! While in college there was a gorgeous set of twins, Anna and Amy, who were both quite active sexually. I was with Anna a couple times and a friend of mine dated Amy briefly as well. No, we never were lucky enough to participate in a foursome but another friend of mine had to fortune to be with them both for an all-niter. As the story goes, the sisters had spied on each other during sex before but this time Amy walked into the room while Anna was getting pounded by by friend Brian. Everyone was apparently quite drunk and Amy removed her clothes and started rubbing Brians ass while he fucked. This led to a few more different positions before Brian blew his load while hitting Amy from behind.