I've seen some films showcasing real sex. Sometimes the main actors are having sex with each other. Sometimes "stunt" doubles are seen having sex. A triplet of movies off the top of my head are 9 Songs and Nymphomaniac Volume 1 & 2. One I saw recently was Love. This movie is darn near a glorified pornographic film. People in the sex scenes are actually having sex. There is even a hand job scene where the camera is in front of the penis as it ejaculates. That is a perspective I've never seen in main stream porn; it was quite amusing.

I didn't enjoy the film. I get that it's trying to be artistic but it didn't do it for me. I found it bland.