Apparently it is real, and taken a few years ago. Perhaps after her divorce?
It's real, and from a 2010 GQ article, read it here
There are more photos at the magazine GQ
And she isn't bashful at all. Take a look at her interview with Howard Stern around 2:25 in the video.
This is another great example of the feigned outrage of the liberal elites. Nobody cares if Megyn is posing while tugging on the straps of he lingerie, or if she is being interviewed, live on a radio show, and she is discussing intimate details of her sex life, but she pretends that she is shocked by Trump talking crudely about women in private.
That said, some might say she is probably still "Not Guilty".