Threesomes (especially FMM) are popular in vampire stories. Whether this be the trinity of girl/vampire/werewolf or girl/vampire good/ vampire bad or even girl/vampire/human. (Think Twilight, Blood Ties and Vampire Diaries). So why are threesomes so darn sexy? And why is the idea of a woman being the erotic focus of not one, but two men, often such a compelling sexual fantasy?
In romantic fiction (and in the vampire series) the sexual tension arises from the fact that the female protagonist is attracted to both men for different (and often contrasting) reasons, and endures an emotional battle because she feels she has to make a choice (usually after trying out both guys first!). And what makes it more erotic is the fact that both men in question adore her.
But why does she have to choose? Now, you are unlikely to see Bella or Elena having a threesome, even if the idea is a turn-on. The menage a trois is a fantastic dramatic tool for a writer, and in erotica the fantasy can be explored much further.
I can say from personal experience that enjoying a threesome with two men simultaneously is wonderful - more so if you care deeply for both lovers. I have also tried BDSM threesomes, once with a lover and a total stranger (his friend), which was exciting and thrilling in a different way. The sheer physical possibilities of this combo can be mind-blowing. Emotionally, giving and receiving with two lovers and ensuring that everyone concerned gets plenty of attention is to be recommended.
FMM features in a number of my erotic short stories, (in fact, 2 out of the 3 stories in my collection Love Bites involve threesomes). Who says three's a crowd?