For some movies, this is certainly needed. Or their is some deeper layer from the director which either purposely hidden (to be explained later) or fail the give enough context to figure out clearly.
That would ruin the movie for me. I don't have any trouble following the plot.
Porn movies should come with an alternative soundtrack. Chirping birds, construction site noises, whistles and bells - also organ music, when the organ in question meets its wiggly little pal.