Here's a link to the yarn - http://www.patonsyarns.com/product.php?LGC=grace It's a very thin cotton. Hobby Lobby's synfonia would be a substitute, possibly Lion's Microspun. The '
slinky, sexy and tight' comes from the pattern as much as the yarn. You'd want to knit a size that ends up smaller than your bust measures, perhaps 2-4", then you'd get form-fitting.