This is a twisted plot of sexual satisfaction. A brother and sister tend to get what they want no matter what. The problem for the brother is that what he wants is sacred to his lady friend. Some things conspire during the movie that cause complications for the guy Sebastian. The end isn't always pleasant.
Lets flip the script a little.
What if in these movies women were out to get so. What if they made a movie were the ladies wanted to get some and would do whatever to get it, how would they be viewed. If women were to make movies of this nature, then they would be seen as hoes or sluts.