Autoeroticism
Autoeroticism (also known as autoerotism, autosexuality, or self-gratification) is any sexual activity involving only one participant. It is the practice of giving sexual pleasure to oneself.
The term was popularized toward the end of the 19th century by British sexologist Havelock Ellis, who defined autoeroticism as "the phenomenon of spontaneous sexual emotion generated in the absence of an external stimulus proceeding, directly or indirectly, from another person".
The term masturbation has a similar meaning, but is not synonymous; masturbation is only physical stimulation of the genitals by oneself while autoeroticism encompasses a broader range of activities such as nocturnal emission, sexual fantasy, and sexual arousal to 'sexually-neutral' stimuli (music, scenery, art, risk, spiritual reverie, etc.), which can be maintained by the self.