Disclosure: I received product at no charge in exchange for my honest review.
Bandelettes solves this problem for me. They are made from a glamorous, soft, stretchy lace material that hugs each thigh independently. Each Bandelette has a very thin band of non-slip silicone material along the top and bottom to keep it in place. Each is six inches long so they provide excellent coverage. I just put them on, position them on my thighs and they stay put. They work fabulously and I am so very happy not to have to deal with chafing anymore.
I received one or more of the products mentioned above for free using Tomoson.com. Regardless, I only recommend products or services I use personally and believe will be good for my readers.