Thes are fantastic. I have no butt. But a little belly. A 36" waist. My first impression was they look like a control top of pantyhose. Without the hose. These are definitely not shapewear!! I think I would buy a large. Having no size problems. Maybe rollover. But the XL comes th an inch above my bellybutton. These are more like an elastic boy short. The thigh length is about 3" from the crotch. These are mainly a comfortable liner . When wearing a dress, shorts and pants. They are seamless. So you won't have any panty lines. These are more for thigh chaffing. I haven't  had any problems with rollover.  These are very comfortable. You could wear these around the house. They conceal your privates. These would be excellent for biking and exercising. These remind me of a mens liner. These have very little support. So if you guys are in need of support. These wouldn't help you. Other then thigh chaffing. The gusset is not cotton. Its the same material as the skimmie. When wearing these. It feels like your not wearing anything. Just like a thong. But its a boy short. I highly recommend these. I've worn these about 6 hours. No rollover problems. I think they might wick away any perspiration. But Jockey offers one that does. I might try them. For running, exercising, and yoga. Make sure you order the right size. This is a must have item. Added to your wardrobe. You'll be pleasently surprised!!!