Somehow I can't find these kind of leggings, the ones that are really tight around your butt cheeks and actually look like a second skin. Where the elastic cloth actually goes in between your cheeks, like these:
I believe that this is achieved by buying leggings that are one size bigger than what you "should" get. The extra material around your butt will become a wedgie when you pull the leggings up from the waist. Other wise the leggings are to tight and don't have the extra fabric to "curve" around your butt.
Slinkystylez in Germany have what you want. They have a style called Cheeky wedge which fit ilke a second skin . Look up there website. I have a pair of these Cheeky wedge leggings in the elastileather 390 and they are a brilliant product and really well made. They definitely fit like a second skin- but Don't go a size smaller than what's recommended. Hope this helps.
Unless you wanna wear those super thin leggings to show off in front of your boyfriend, then don't bother wearing them because you will be called- trashy, sl*t, easy to get with, and who knows what cray names guys come up with, girls too. If you wanna show off your curves, buttcheeks specifically, then wear regular leggings or yoga pants. Those are more appealing and attractive... you're classy and showing off at the same time. The choice is, of course, yours.
They're not any special kind of leggings. This look is achieved by not wearing panties and pushing the fabric between your butt cheeks. It looks pretty slutty though. You might as well not wear anything at all.