Erectile dysfunction or impotence is a sexual dysfunction characterized by the inability to develop or maintain an erection of the penis during sexual activity. A penile erection is the hydraulic effect of blood entering and being retained in sponge-like bodies within the penis. The process is often initiated as a result of sexual arousal, when signals are transmitted from the brain to nerves in the penis.

Generally, it is okay for men to lose erection at times. It only becomes a problem when the male organ lacks fullness and hardness and erection is not enough to sustain having sex. When things become a little serious and persistent, that is when it can be called as erectile dysfunction (ED) or impotence. However, it should be not be confused with lack of appetite for sex, orgasm, or premature ejaculation

- See more at: http://www.healthflava.com/erectile-dysfunction-causes-and-treatment/

If you find it hard to maintain a hard on or get your manhood up, the above post is for you.