Sexual Act. During the act of heterosexual coitus, a hand is inserted into the vaginal cavity and "jerks" or "jacks" off the male penis. A similar action is engaged during homosexual coitus. Those without penises may use devices to replicate a penis such as a strap-on or dildo.
This act was the reason, much like sodomy was to Sodom, God destroyed Gomorrah.
In the middle of Hot 'N Horny Co-Eds III: Hos in 3-D, a man does "Gomorrah" a woman for no less than 3 minutes as she obviously fakes an orgasm.