Actually, I'd talk to her first. If you don't say anything, and smile out of awkwardness or just to be polite, then I think she assumes you may like the behavior. Don't pretend to be comfortable with it if you are not, because then she'll continue and it could get a lot worse. Tell her you feel it's inappropriate and that she should stop because it's highly unprofessional. If she continues after you've told her to cease, then speak to the higher up that's supposed to assist in these matters. Such as your HR representative, and see if this can be stopped without a lawsuit and without the whole 'destroying her life' thing.
*Or you could flirt back - because apparently in this thread it's alright. It's probably also alright for her to grab at your crotch and treat you like a piece of meat, even if it makes you extremely uncomfortable. Because you're a guy right? You're supposed to want it no matter how you really feel. Like they say, "You are asking for it".* [/sarcasm]
If you feel uncomfortable, then you shouldn't HAVE to put up with it because you are a man. I'm getting really tired of this, 'Men can't be victims' jargon, because everyone thinks you shouldn't have feelings, or be uncomfortable, and be a pig towards everything with breasts and a vagina. Because, "That's what a man does". But trying to utterly destroy someone elses life and taking the up-most pleasure in it, is just disgustingly greedy and abhorrent; whether you are a man or woman.