I did not realize that this needed to be addressed...
If your shirt does not cover your rump or crotch for that mater, opt for skinny jeans if you are seeking the same illusion. There is a lot more coverage in a pant rather than a stretch material. Leggings are a light weight fabric, that usually has a sheer effect because they are meant to be stretched, unless you are one of those really skinny gals and the fabric gathers and hangs... there will be another posting later for you. Either way, do not do it.
Do not put yourself in a vulnerable situation were some perv will actually lie down on the ground to snap a shot like this below, of Paris, to post on the internet and show all his friends that he nabbed a shot of your junk.
Oh, and if you are reading this thinking, "yea this would have totally worked with skinny jeans"! No, no, no young Padawan I have so much to teach you. This would have only been pulled off with skinny jeans and an appropriate layered top. To much body showing and tightness going on is not a good balance. Unless you are trying to start a prostitution ring - which FYI is illegal. Below is an appropriate way to wear leggings without being overexposed.