A gangbang is where a small number of females have sex with a substantially greater number of males. Although I am not aware of any regular parties, a small number of women do advertise in Yahoo and MSN groups. These are generally priced to cover the cost of a motel room (remembering that some guys say they'll attend but then don't show up, leaving the organiser with a financial loss).

Guys, bear in mind if you plan to attend such an event that there is simply no hiding; you will be required to get it up in front of a whole lot of other guys. If you suffer from stage fright, a gangbang may not be for you.

A variation on the gangbang is the bukkake party. Bukkake is an activity originating in Japan where a large number of men all ejaculate onto the face of a single woman. The term can also be applied to an all-male party. It seems to me that bukkake is an activity designed less about sexual pleasure and more about humiliating the woman; after all, the guys are probably masturbating and there may be no direct physical contact with woman at all. Needless to say, (hetero) bukkake parties are less common than some people would like them to be, principally due to the difficulty of finding a woman who's interested in having eight or ten guys all come on her face. Gay bukkake parties are probably easier to organise if you really want to due to the relatively greater ease of finding both donors and recipients.

This site deals mostly with the nuts and bolts of alternative sexual activities. It does not deal much with emotional aspects. People considering engaging in partner-swapping activities should consider carefully the emotional consequences of seeing their partner having sex with a stranger.