Some skinflicks have musical soundtracks. Most of them don't; the movies often have a very low budget, not nearly enough to pay a composer and some musicians for original tracks.
Only just now did I clue in to how they can get away without the services of a composer:
The music in 1984's First Time At Cherry High is "Santa Claus Is Coming To Town" played on a saxophone.
I Am Absolutely Serious.
I felt it so urgent to bring you this wonderful news that William Jefferson Clinton completely lost his stiffy. I don't think I can go back to that cinematic masterpiece without howling with laughter.
Now this is serious:
All of my own compositions are licensed with Creative Commons Attribution-ShareAlike. That means it's quite likely that Recursion on an electric guitar provides ambience for some guy's humjob.