Sleep masturbation is a form of sleep sex, or sexsomnia, in which a person engages in masturbation while they are asleep. All forms of sexsomnia, including sleep masturbation, are a form of parasomnia, or sleep disorder. Other parasomnias include sleep walking and sleep eating. In all cases. the person is not conscious while engaging in these activities, and in some cases cannot be roused. In most cases, people also do not remember engaging in these activities when they wake up the next day.
Sleep masturbation was first reported as a clinical disorder in 1986.
A 2010 study found that sexsomnia may be more common than many people think; it found that 7.6% of patients at a Toronto sleep laboratory reported sexsomnia, including sleep masturbation. That said, this study examined people at a sleep disorder clinic, not a broader population.