Also just a thought, you say that some girls look like they are in pain - have you ever watched yourself having sex? It's not always pretty, and sometimes pleasure faces can be similar to looks of pain. Orgasm faces alone prove that.
The pained look may also be from holding the position too. Sometimes positions are difficult - especially with the symantics of a DP - and you can get a bit uncomfortable while holding the position while getting the shot. There is also the added bonus of having to "cheat" to the camera so you can see the hardcore, which can make things a bit more difficult. But normally this uncomfortable position holding is only for a minute or so, that is just part of the job.
I just blows my mind that so many people think we do sex acts that hurt for the viewers enjoyment. Fuck that. Furthermore all a girl has to do is say "stop" or "ouch" and the performers and the camera stops rolling. That's the way it is.
As far as the gaping/jabbing, I agree with the comment above, if the ass is relaxed and open, it's not going to hurt.
And I know this may come as a shock but we do ham it up for the camera. Guys and girls. I am not saying we fake it or are not having fun but in order to make yourself heard for the camera you have to talk and make a bit louder sounds. That's just the way it is. When you are having normal sex you might whisper dirty things to speak softly to your partner, in a sex scene you need to speak up. Same with moans and sex noises. Mine are real, I assure you that, but they are louder on the set than at home.
I have also encoutered people who will ask for a painful look...I encountered this recently while working with Shorty Mac (he is enormous, no really, the biggest cock I have ever seen or fucked - and we did anal), we were doing the stills (photos) and they asked me to "give a painful look, like it hurt because it was so big". I personally am not too keen on that sort of thing but I also realize there are people who get off thinking it hurts a girl to take a cock that big. And for the record, no, it didn't hurt, it was a bit tight until I relaxed but I really wanted to see what a cock that big felt like and once I got it in it was fabulous and felt good and I really got off on it because I was doing something so dirty and was so filled with cock. (Do I want a cock that big every day? Nope, but now and then it can be fun.)
Well, normally I give my 2 cents...this time there is about 6 cents worth. All my opinion, your mileage may vary.
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