A: Why do you have headphones by your home computer?
B: sometimes I like listening to music while I work.
A: Yeah, but you have speakers and you live alone. Seems to me like they're your pornphones.
B: I don't watch porn.
A: Bullshit, and your pornphones are exhibit A.
A set of headphones which have only one speaker working. Are named pornophones because they are often used by 13 year olds to watch porn without being heard.