Everything has to be intrinsic plot-wise in the same way, to use the Linda Williams analogy but to move it on a bit, as musicals - in old musicals, like in an old Cole Porter musical, you get the action, then they do a song, which reflects a moment - everything stops while that is being sung - and then you restart. These days in most musicals, the plot keeps moving through the song. I think it would be nice if someone constructed some pornography where the sex continues to propel you through the story.