While the previous chapter established the ways in which players incorporated sexuality into their role-playing games, this chapter looks more specifically at the rules used to do so. Rules, as described in Chapter Two, function to limit and shape play into structured games (Suits 2005). Although Suits’ definition of rules focuses on their mechanical function in organising play, there is an additional social function as well. Using Goffman’s idea of a primary social framework (1974), some researchers have noted players develop their own sets of rules to govern the social aspects of playing. As elaborated upon in Chapter Two, the primary social frame functions in games through the development of exogenous or social ‘house’ rules (Björk and Holopainen 2003; Montola 2008). Exogenous rules are as necessary to game play as the ludic and mechanical endogenous game rules since they generally dictate expected behaviour outside of the game that inevitably influences the content and themes accessible for play inside it. Additionally, the themes and concepts present in a game’s history and lore present themselves as diegetic rules, which dictate acceptable social behaviour for characters. As this chapter will demonstrate, these three types of rules do much to influence the inclusion or exclusion of erotic role-play.