Well it's not like you can put it in a cast...
Penile fracture is a medical emergency, and emergency surgical repair is the usual treatment. Delay in seeking treatment increases the complication rate. Non-surgical approaches result in 10%-50% complication rates including erectile dysfunction, permanent penile curvature, damage to the urethra and pain during sexual intercourse.
Causes
In the western world the most common cause, accounting for about 30%-50% of cases, is intercourse. Of those, partner-on-top position resulting in impact against the female pelvis bone or perineum and bending laterally are most common.
The 'reverse cow-girl position' is notorious in the aetiological cause of penis fracture. The pathogenesis involves the woman bending the erect penis ventrally beyond the tensile strength of the tunica albuginea causing it to fracture.