I first bought a pair of 2XU tights on the recommendation of a running mate who felt they really cut down on DOMS after long runs. I tried on various sizes in a local shop and bought a pair. Years later when these were showing lots of wear from frequent use I went on line to buy some more, as the shop no longer stocked them, but could not remember what size I had been wearing - the initial pair were labelled M but was that "Medium" or Male? I messaged them with my height/weight and they felt I should get "Small" as per their sizing chart, or even the next size down if I wanted lots of compression. I opted for "Small" and have been wearing that size ever since.

I find them comfortable around the groin - the only slight issue is how tight they are around the ankles - they can be quite hard to get off, especially when damp/wet.