parts of your body that can become hard and erect. present, for example, in the male penis when the male in question gets an erection when he becomes sexually aroused.

the mechanism of action is analogous to how Reebok pump shoes worked. in the body, parasympathetic action causes the veins draining the erectile tissue to constrict. As blood gets trapped, causing the whole thing becomes engorged with blood and therefore become erect.