You can buy e-stim boxes especially made for zapping the nether regions on males and females alike. One of the configurations on the ET312, called "tri phase", combines a two-conductor plug placed near the prostate with pads placed at each feet, and the end result is utterly wild. It's really unfortunate that most guys are too hung up about their own bodies to explore it.
ET-312 software interfaces are some of the most advanced out there right now, too. The community at http://smartstim.com is absolutely amazing to watch.