When a man is fucking a girl either in the vagina, or in the anus, and tears through the skin separating the two. His penis is then in both of her orifices, and she is probably bleeding and screaming. Space docking can be accomplished either by entering the vagina, tearing through and exiting the anus. Or by entering the anus, tearing through, and exiting the vagina.
Guy1: Damn man, last night Suzy and I were fucking and she was laying on her stomach, and I was sitting on top of her facing away from her head, fucking her in the ass. And I fuckin pushed in hard, and next thing you know I pushed out of her fucking vagina!
Guy2: Either you have fucking Cheshire cat dick, or you space docked the shit out of her! Her pussy is gonna need some serious stitches. Sounds like your life is going to suck for a while. Have fun with your blue balls.
Guy1: Hey man. Whoa. Her pussy is busted. Not her mouth.