wraeththuWraeththu: From Enchantment to Fulfilment is an RPG originally from Immanion Press based on the books of Storm Constantine, one of the first teen goth fantasy horror alternate sexuality writers.

The Wraeththu are a sci-fi post-apocalyptic species which evolved from humanity and have a thirst for hermaphroditic sex using their twin set of male and female flower-like genitalia. Their sexual acts form a basic part of their health, magic, and healing process. While the source material probably includes more than just sex and violence, the RPG pretty much discards all but these elements.

It’s considered a fairly awful game. Skill checks for those with minimal training are more likely to fail than for those with absolutely no training. (source) As for the role playing aspect, the characters themselves are supposed to be nearly incomprehensible sexual predators, thus unplayable. (source)