A Shy Exhibitionist
My wife is what I call a shy exhibitionist...she doesn't like to wear overly revealing clothes or put her sexuality on display if we are anywhere where we might run into friends or co-workers. But when we're on vacation, she'll totally surprise me with what she'll wear. We were going out clubbing in NY one night during a week-long stay and I was waiting around the hotel room for her to finish getting ready and she came out of the bathroom wearing a miniskirt with fishnets and a torn top with strategically placed rips that just barely covered her and pink wig. Totally took me off guard because she sometime dresses up for me at home, but is normally a more 'classic sexy' dresser in public (more the full-coverage cocktail dress type, with the daring part being the slit up side to show some leg). She got a lot of attention and that made for a fun night.
Another reason I say she's a shy exhibitionist is that I've noticed that when she does dress up in more of a trashy-sexy look that the more classic sexy, she tends to hide behind things like the wig or big, dark sunglasses or heavy makeup around her eyes. It's like the more skin she shows, the less of her face she likes to be visible.