When a man inserts his penis into a woman with a missing eye's eye socket.
man 1: dude guess what i did to this chick last night
man 2: what?
man 1: i gave her the one-eyed pirate
man 2: nice work dude!
When one proceedes to bang a girl, pulls out near ejaculation, skeet in her eye, and finally kick out her shin. Now you have a pissed off, one-eyed, one-legged, bitch chasing after you. Hence, the one-eyed pirate.
Tom was prepared to run for his life after giving his girl friend a one-eyed pirate.