I've got chunky thighs, and wearing skirts/dresses with nothing to serve as a barrier is a guarantee for heat rash.  These fit comfortably, and keep my thighs from rubbing together.  There's no compression, these aren't Spanx, but if you want something sleek and smooth for under dresses, they fit very well.  Also, I have a thick tummy (matches the thighs, lol) and the waistline doesn't roll!