The act where two homosexuals forcefully try to convert a third individual.
Bill and Joe were carefully approaching Bob from each side of the bed. Bob, unaware, was now becoming a victim of a San Francisco Sandwich.
When a guy and girl cum on each other and rub the cum all over each other's bodies. The girl then lays on top of the guy with the guy's penis being the pickle and the girls boobs being the meat in the sandwich and the couple can add whatever else they want in between to put their own special touch on the sandwich.
Man that girl is hot. I wonder if she'll make a San Francisco Sandwich with me.