Doppelganger Porno
A porn video or movie that features someone that looks a lot like, but isn't, somebody you know, doing the nasty. A few times in his life, a man will stumble across one or two of these.
"Wow, that hot chick banging that guy on screen sure looks a lot like my hot friend that i'll never have sex with. AWESOME! Looks like I found a doppelganger porno!"