Simply said, penis rock is music that is played by rock bands that have no talent and think that if they are loud enough, people will like them.
Metallica Matt: Why are you listening to that penis rock when you could listen to Master of Puppets or And Justice for All.
Hardcore Hank: I'm listening to Slipknot's "Pulse of the Maggots."
Iron Maiden I Can't think of a name that starts with 'I': Why the hell do you like that penis rock? That is Slipknot's worst song.
Blood Brothers Berry: I like the Blood Brothers' early CDs, which involve much pounding and screaming.
The Spirit of Dimebag Darrell: That would be penis rock, but the lyrics are deep and meaningful (as only the God of Metal like me would understand). Pantera is awesome.
Sean- I thought the only penisrock band was Nickelback?
Mike- Oh wait that's true.