I don't know how it does it, but this sportsbra I bought (of which I'm not going to mention the name because it's been discontinued and I don't know that there aren't people my size reading this) a) prevents anything from moving around, at all, ever, even while kickboxing (yes, I tried a slightly toned-down form of kickboxing in the dressing room), b) makes my breasts point upward, hence making my whole torso look slimmer, and c) looks completely smooth under a tight t-shirt. So obviously they have to discontinue it. I found one in my size, but I really want a second so I can have one for exercising and one for normal wear, rather than having to wear a sweaty bra whenever I want to wear an unforgiving top.