OK,Now that I've gotten into a creative mode, here is another idea.
There is not nearly enough hardcore sex in public. To be clear, there is more then enough "sex outside" in private backyards and secluded wooded areas and cars. What I am talking about is sex in public. In addition, what little public stuff there is tends to be flashing or quick furtive blow jobs. What I am talking about is actual hardcore (ideally anal) sex in public places where real people are passing by.
There is a really great German Fetish series put out by Kit Kat/Subway called Breaking Taboos that has these beautiful women walking around naked in public (often with pussy clamps and butt plugs in), and having public sex. I've heard that the recent Ass Obsession 3 release has a little bit of public stuff, but I don't know what it has.
The key to filming these scenes would probably be to go overseas to areas with A) looser morals, B) weaker anti-nudity laws, and/or C) Bribable police forces. Here's a few additional ideas though.
1) In the USA, head for party areas. I bet you'd be able to get a lot more leeway During Mardi Gras in New Orleans or Fantasy Fest in Key West. Overseas places like Cancun might be even better.
2) Public Sex doesn't necessarily mean outside. How about sex in a busy nightclub or discoteque (not a strip joint though, that's corny). In Berlin the Kit Kat Klub periodicly has wild public sex parties where all the local fetishists come and dance wildly and have lots of sex in public. Is there anything like this in the USA?

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