Last month my girlfriend (Sarah) and I took a short vacation to San Diego with a couple that we’re friends with (Ben and Allison). All four of us are in our late-20s, active/athletic, and have known each other for a few years from the girl’s working together. None of us had ever done anything like this before and even though I had always wanted to try a threesome or foursome I never expected it to actually happen since my girlfriend and I are generally conservative.