They are such a mainstream wardrobe staple now, though some people seem to still be confused about what to wear with leggings. Simply put, if your entire behind is exposed, the shirt is just too short to wear with leggings. If you are comfortable with something that only covers half of your behind though, that's up to you. BUT if you want a no fail option, go for something that falls below the bum like a thin cardigan, or a tank top with shrug or blazer. If you go with something chunkier though, I would opt for a vest or an open cardigan, so you can leave it open at the front to avoid adding extra bulk to your frame. Add some boots or ballet flats, and you are good to go!