Alan Moore has written a great essay on the history of pornography. This snippet on Victorian dramas is particularly charming:
Pornographic playlets could be purchased, ranging from two-person dramas through to full ensemble pieces if the neighbours were agreeable. These publications came with sheet-music, so that if one of the participants were musically inclined then he or she could sit at the piano and provide a vigorous accompaniment to whatever activity was taking place upon the hearth-rug or the horsehair sofa. Yes, I know it sounds ridiculous but I was told that by Malcolm McLaren and if you can’t trust Malcolm McLaren then whom can you trust?