The first and only time I ever heard that term was in relation to the TV series “Torchwood” where the “hero” is a human-looking being who appears male, but is so evolved (according to the story) that the concepts of male and female are irrelevant to him. So basically, it is bisexual, but with the additional concept that there is no gender identification, only pleasure.
It was a good show until that concept was introduced. I don’t know what happened after than. Don’t want to know!
I watched “Torchwood: Miracle Day” last week. That character thoroughly creeped me out. That greasy smile, the big puffy red lips, the teeth....yeah, I can see why they picked him to roll around with men on camera. Ugh.