BDSM
Many of the most common sexual roleplays involve a power differential and form part of the dominance and submission aspect of BDSM. Roles can be general designations of power positions, or very specific, detailed fantasies. Some people, such as those living the Gorean lifestyle make use of an entire imaginary world. The controlling player is often called the top or dominant while the controlled individual is called the bottom or submissive. It can be considered dangerous and therefore a safeword is advised to continue the safety of other(s) in such acts.
Read more about this topic: Sexual Roleplay