Erection is the hardening of the penis. Erection starts in the brain after receiving a stimulating impulse. The blood then runs to the penis causing it's hardening. Every man experiences erectile disorder from time to time, even if aroused beforehand. Since the penis does not harden enough, sexual intercourse is not possible. If the disorder is continually causing discomfort to a man, he should seek medical help. When is the right time to consult a GP? Watch the video.