Wankadox
Building your muscles makes them larger. Still, years of aggressive masturbation doesn't make your penis grow any bigger. That's a sexual paradox.
Jill: Tom left me the same day as I got my boob job!
Robert: Ah, now THAT's a wankadox. Can I feel them, please?
Robert: Ah, now THAT's a wankadox. Can I feel them, please?