We evolved according to the natural rhythms of darkness and light; our bodily functions reflect this and undergo similar fluctuations. They perform best when we live in accordance, as much as possible, with these cycles.
"Sexsomnia" sounds like a made-up, weird word, but this appears to be a sleep disorder. While doing research for a recent TV appearance , I investigated what looked like a new and intriguing parasomnia.
In an editorial about sleep violence, a man chronicles what it's like to commit violent acts in his sleep (granted, his didn't go much further than punching the headboard or acting like a defensive lineman).