Uhh what. Is it even possible for your penis to break? I've never heard of anything about it being possible.
It's what we call penile fracture. It is a severe form of bending injury to the erect penis that occurs when a membrane called the tunica albuginea tears. The tunica albuginea surrounds the corpora cavernosa, specialized spongy tissue in the core of the penis that fills up with blood during an erection. When the tunica albuginea tears, the blood that is normally confined to this space leaks out into other tissues. You get bruising and swelling.
http://www.scientificamerican.com/article.cfm?id=can-you-really-break-your