Dave was having an argument with his girlfriend. She was saying how it's unfair that if a bloke fucks a different girl every week, he's a legend, but if a girl fucks just two blokes in a year, she's a slut.
So, in response, Dave explained that if a key opens lots of locks then it's a master key, but if a lock is opened by lots of keys then it's a shitty lock. That shut her up.
