Penis and Rubik's Cube Commonality

The joke uses the similarity between a penis and a Rubik's cube, both of which can become "harder" the more someone interacts with them. It's a play on the word 'hard', which has both a literal and a sexual connotation.

• Penis
• Rubik's Cube
• Sex
• Common
• Play
• Anatomy

• Do you think you can solve a riddle about my penis because I don't think you can... It's too hard.
• Why do men find it so difficult to solve puzzles after taking Viagra? Because they just keep getting harder and harder!
• Why are life and a penis alike? Women make both of them hard.
• What's the difference between a dick and a rock? One's hard.