Some men have a penis that curves to the side, upward or downward when erect. This is common, and a bent penis in most men isn't a problem. Generally, a bent penis is only a cause for concern if your erections are painful or if the curvature of your penis interferes with sex. When you become sexually aroused, blood flows into sponge-like spaces inside your penis, expanding and stiffening it. A bent penis generally occurs when these spaces don't expand evenly. Most often, this is due to normal differences in penis anatomy, but sometimes scar tissue or another problem causes a bent penis and painful erections....