Your average porn video last about 30 to 40 minutes and most of that time is dedicated to just the sex and that includes the ones that have a small scenarios. To shoot something like you described would mean shooting hours of extra footage that is not connected to the sex portion of the scene.
The closest you get in this day and age to what you are looking for is a site like Backroom casting Couch where you get a pretend interview with what appears to be true first time porn performer but we all know that the woman knows what is about to happen because she had to get tested prior to shooting the scene and hopefully agreed to a certain rate based on what she was willing to do on screen.
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