First off, SUPER CUTE AND SEXY. My thighs measure 25.4 inches and I got the size C fit perfectly. I bought them for vacation. I wore them once to test them out, they stayed up on my legs all day great at work where I sit at my desk, then I took about a 2-mile walk on my lunch to see what they can do. My issue is that the coverage wasn't enough and the lace itself started to irritate me by the end of the day. CHAFING WAS DEFINITELY LESS THAN NORMAL. But I believe the way I walk makes my thighs rub together in funny places like lower on my thigh or closer to the crease where my thigh meets my pelvic area. GREAT IDEA, I think the plain cloth ones would be better for active use, I wish they came in an extra long size bc the design is brilliant!