Super helpful to hear about others' experience with this. I just started riding TTs this summer. I had some very significant swelling (mostly on one side) the first time and continue to do so with each event. My husband said that now we have three testicles between us!

After reading these posts I think I also can decrease this unwanted effect by tipping down my nose. Makes perfect sense. I have an unusually dropped position because I race as stoker on a tandem. To decrease my resistance I ride gripping the top tube under my captain's seat. Not very comfy but I have virtually no upper-body wind resistance. I'll give it a TT trial!