Even though there are no actual bones in a boner, it is possible to break one's penis. To understand how this incredibly rare and painful event can occur, we first need to review a little (or not so little) penile anatomy. The shaft of the penis is comprised of two chambers of spongy tissue, the corpora cavernosa, which run along the inside length of the penis. Erections occur when, in response to physical and/or mental triggers, the nerves of the penis signal the surrounding muscles to relax, allowing blood to pour into the corpora cavernosa. A thick membrane surrounding the corpora cavernosa, the tunica albuginea, keeps the blood that is being pumped into those spongy chambers from being able to escape. The result — a stiffer, larger, and more rigid rod. Although your erect penis may feel rock-hard, it is still flesh and blood.
