Turns out this condition is technically referred to as "perineal symptoms" and there's been a lot of content around it thanks to commercial development of seats designed to relieve pressure on the perineal area.
I'm not yet ready to invest in a new saddle, so I've been looking around at what the Google has to offer in response to "bike perineal symptoms" and trying not to get scared of all the ED mentions alongside the perineal symptoms.
The best advice I've seen so far is an article over on MedicineNet.com about Groin Numbness and Bike Riding where they give the following recommendation on how to prevent perineal symptoms:
- 1. Stand up frequently on the pedals to take pressure off the perineum.
2. Change your position on the saddle while biking. Shift forward and backward when you ride to eliminate pressure on just one part of the perineum.
3. Experiment with adjusting the angle of your saddle so that it tilts slightly downward.
4. Wear bike shorts. They have chamois padding in the perineal area that will help relieve pressure.
5. Adjust the height of your handlebars slightly until you find a comfortable position. Handlebars below the saddle may work well for road or racing bikes, but perhaps not as well for touring or hybrids.
6. Make sure that your seat post is adjusted to the proper height. Your knee should be just slightly bent at the bottom of the pedal cycle.
7. Limit the number of miles that you pedal. This may not be desirable for all riders, but number of miles per week can be a factor.
UPDATE: Great to see The Climb blog over on NYTimes.com tackling this "intimacy numbness" issue today. Great content in the comments so far, especially the link to this Bicycling Magazine story debunking the link between saddle time and ED.