I wear either the Sugoi (not a clue sry) or the Performance Ultra Gel Shorts for all my rides rather they're 12 miles or 112 miles. I don't use any chamois butter or creme and I don't have any problems but..........I have a Great saddle and I've made sure it's set just right for me.

If the Flex shorts still don't work for you, you might want to consider a saddle change. To each her own but if you're riding the saddle that came with your bike - it's probably a Bontrager. I and several other women here think the Bontrager was made for the sole purpose of torturing it's rider!