Many men have a mild natural bend that does not cause any problem during penetration. However, when the curvature becomes too prominent or when tissue changes occur inside the penis, sex can become painful for one or both partners. This pain can affect pleasure, erection quality, self-esteem, and relationship confidence. Understanding Penile Curvature A curve in the penis may be: 1. Congenital (since birth) This type develops naturally. The penis may curve left, right, up, or