I've been involved in MFM, and MFF. The MFM was just three single friends having a good time, it was great. MFF was after I was married. My wife and her friend just kept one-upping each other until there was no going back. Lots of sheepish looks the next morning, and some very harsh words and a divorce when the friend confessed to her hubby. Hmmm... Hot tub and alcohol involved in both...