I meant to ask last night if you had tried hula hooping since you are trying to define your waist? I bought a 5 pound weighted one a year or so ago and, while it feels like my innards are being beat a little, it killed my belly fat pretty quickly. You are already really little so maybe you could go with the type girls use at festivals? My best friend is a huge hoop fanatic and makes her own and it's fairly easy and the colored tape on them adds a little weight. They are way easier than normal hula hoops (I can't keep the little light plastic ones up at all), and they are fun! I got really into it for a while and it gave me killer sides that I didn't have before.