A Raccoon Baculum

Basically, your Johnson is like a sponge or balloon that literally fills with blood. When it's at full sail, the blood flow is cut off, producing a stiffy. And while you probably know that there is no bone in the human penis, the baculum or penis-bone is common in most mammals, including chimpanzees and gorillas. And even though there is no bone in your boner, a klutzy move during sexytime could cause you to break your penis. OUCH!! Be careful out there!!!