I've looked for an inspiration that centers on a mirror for a long time now. This one is nearly perfect both in its simplicity and in its deceptive depth.
The essential hotness is the mirror itself, to be sure, but the way the mirror is divided into individual panes, and above all the way it is placed in a frame, add to the effect greatly. The individual panes break the reflection up, the way only the owner of a thing can do to that thing (as well as assuring the viewer that it's possible to put a lot of vigorous weight on the table, which is an important part of the fantasy the image generates!). The frame speaks even more of ownership: the woman is owned, and her reflection is owned, for both are framed in gilt.
That's where three other elements come into play: her position, which it is very easy to imagine is something that has been commanded by her owner; the height of the table, which will make it easy for her owner to enjoy her; and the lingerie, which serves as a mirror (if you'll allow me) of the frame, framing the woman's charms and demonstrating her owner's possession of her.
Then there's the general elegance, which "rhymes," each element with the others, from the beautiful wainscoting, to the gilt frame, to the woman's lace stocking-tops and above all her lace panties. Her hair and her bracelets add a very light note of dissonance, making one think of the indignities that might be visited on her in such a scene.
And, then, there's the way the angle of the shot, which shows us without showing us what it is she sees in the mirror, lets our fancy play upon it, and then reach out to imagine what she might see there as the scene continues.