How is an erection maintained?

To keep an erection, your body stops the extra blood that has been sent to the penis from leaving.

The picture below shows how the inside of the penis looks when the penis is erect. If you look at this you'll see that your body keeps the blood inside the swollen erectile tissue by shutting off the blood's exit points (or veins). By doing this, the blood is trapped inside your penis. This allows your penis to stay erect.

What your penis looks like on the inside when it's erect


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