Three American GIs are stationed in Belgium in World War II. They know they're about to get shipped out to the front lines, so they decide to make the most of their lives while they still can. In this pursuit, they decide to go to a Belgian whorehouse.
They go up to the proprietor of the place and say "Look, Mac, we're about to get shipped out to the front lines. We're looking for the time of our lives before we go. Give us your best hooker, the price is no object." So, the proprietor tells them, "Ok, I know just what you are looking for. Go all the way down the hallway, last door on the right. The only thing is, you must go in one at a time." They agree and pay the man, and then make their way down the hallway.
The first GI goes in, and he sees a beautiful, buxom, bombshell blond lying on a bed with red satin sheets. It's the most beautiful woman he's ever seen, and the flattering red dress she's wearing helps. He gets hard just looking at her. The two of them get undressed, and she turns off the lights, so that it's pitch black in the room.
All of a sudden, the guy starts getting the best blowjob he's ever had in his life. I mean, there are fireworks going off in his head and everything, it's that good. It would be amazing enough if she was just giving him the blowjob, but while she was doing this, she was singing bits of opera in the most beautiful voice he'd ever heard. He would have been moved to tears by the voice if he hadn't been... somewhat occupied.
He finishes rather quickly, gets dressed, and leaves the room, telling the other two GIs, "That was definitely worth the money. I can't even describe it, you have to see for yourself."
So the second guy walks in, and same deal. The blond's lying on the bed, they take off their clothes, she turns off the lights, and she starts giving him the best blowjob he's ever heard while singing in the most beautiful voice he's ever heard.
He finishes and leaves the room, and tells the third guy, "Joe wasn't kidding, she's dynamite! I mean, you go in there, and she's the most beautiful woman you've ever seen! Then she turns off the lights, and she starts blowing you while singing opera! It's amazing!"
The third guy thinks something fishy is going on. He goes in, the two of them get undressed, and the whore turns off the lights. However, before she can start blowing him, the third GI walks over to the light and turns it on.
And there on the table is the glass eye.