Trial and error is the only thing that works. I still get it during 70.3 races that lasts for several days afterwards. When I got started, I tried to vary my position and frequently stand for a few seconds to give the blood chance to flow. I find the Profile Designs Tri Styke to be the best--for me (tried the Selle SMP too, which I like better for road riding), though many have found success with the Adamo.