It's common for the penis to curve slightly to the left or right when it's erect. Peyronie's disease causes the penis to become curved when it's erect. a curve in the penis when it's erect (usually it curves upwards).
Many men have a slight curve in the penis. As long as there is no pain or problem with sexual performance, men with a slightly curved penis should not be concerned. In Peyronie's disease, inflammation and scar tissue form along the shaft of the penis.
Many mammals — including most other primates — have a penile bone, which aids in reproduction and gives the erect penis its structure.