Imagine some soft, breathable, affordable tencel against your skin. Also imagine that it isn't so heavy that it pulls down and sags. This "yarn" is actually a tiny i-cord tube! It is hollow! If you knit it to gauge it will hold its shape. But you can also knit it loosely and it drapes wonderfully. So you have options.
100% Tencel (sustainable rayon made from trees)
size 9 (5.5mm) needles or I-9 (5.5mm) crochet hook