Slash fiction is a genre of fan fiction that focuses on the depiction of romantic relationships between characters of the same sex. Slash fiction involving female characters is also referred to as femslash.
Early on in Star Trek's history, fans speculated on the nature of the deep friendship between James T. Kirk and Spock, adding a sexual dimension to the relationship. This pairing is known as Kirk/Spock, often abbreviated to K/S. Pon farr is often used as an excuse to get the men to bed each other.