Good tight bike shorts are the thing. They should take a little bit of effort to get into. No underclothing! After you get settled on the saddle, reach down into the shorts and pull everything up, fold it over, whatever you need to do. I try to be a little inconspicuous when I do that. It'll stay put in good tight shorts.

Yeah, level saddle. If your bars are much below your saddle, maybe a Brooks isn't the best choice for perineal comfort.