When you get into porn, you DO know exactly what you're getting into.
I've never worked in porn, but I did do some research into this because of exactly the attitude that your comment exudes. That (your) attitude is, "you have implicitly given consent to anything being done to you sexually because you work in porn.” But that is exactly backwards.
If you make a film with body contact, you have a contract which states explicitly what you're being paid for. That and ONLY that is what is allowed. Not only Ron Jeremy, but also James Deen (I think that is how he spells it) is in /has had legal problems because he has taken liberties with what the actresses are being paid for. With Jeremy, it has gone so far that he apparently thinks him being a porn star gives him the right to assault people in public.
Note my first sentence of the last paragraph. If Mark Ruffalo as Bruce Banner is contracted to kiss Scarlett Johansson as Black Widow in the latest Avengers film, you can bet your ass that if Mark grabbed Scarlett's tits during the scene he'd be facing a lawsuit. It is no different for adult film actresses, whether the cameras are rolling or not.
[edit] Forgot to close my quote in the first paragraph.