Safe to say she's had a boob job, although I'd have to say it doesn't look bad on her, at least she didn't over do it
Well, the answer to that question question is, Lingerie, of course.
Back when Catherine was a fashion model she learned how to pose alluringly in expensive undergarments.
In those days she would go home, or shopping, after the photo session.
These days, to the great delight of us all, she stays on and gets her bum fucked.