FAP is masturbation.
Fap is the act of self-stimulation of the genitals to achieve sexual pleasure.
Fap or masturbation is a normal and healthy sexual behavior that is engaged in by people of all ages and genders. It can be a way to relieve sexual tension, explore one's own body, and enhance intimacy.
Please note that the usage of "FAP" is considered to be vulgar slang, and it is generally not appropriate to use it in formal or professional settings.