The act of one male having intercourse of the doggy style position and the female eating out another female.
Gary was a superb Submarine Commander plowing Rhonda from the back and ordering her to eat out Melanie.
The sexual act of scissoring underwater.
Guy 1 - Jesus... Did you see the video with the two lesbians?
Guy 2 - No, what were they doing?
Guy 1 - The Cat Submarine.