When you are masturbating to the point BEFORE the climax, then when a girl comes into the room you pull down her pants and stick your penis inside her pussy. Since you were about to reach your climax, you end up having an orgasm in her vagina.
*guys sticks his penis into girl's vagina without her consent and has a flash bang*
Girl: How did you have an orgasm one second after raping me?
Guy: I was masturbating before and I just had a flash bang.