Considering the things actresses do in film today, we're talking a very fine line indeed. Halle Berry won an oscar for showing her tits to the world, having them fondled, and simulating doggie style with a guy named Billy Bob. Chole Sevigny gave an entirely real blowjob to Vince Gallo on-screen and called it "acting." And should we mention Sharon Stone?
How many female movie stars haven't been nude, fondled, and engaged in sexual contact with co-stars on screen? How many of your co-workers have you seen naked?
The question is just how many sex scenes in the movies weren't simulated...