A death erection (angel lust in medical slang) occurs when a male individual dies vertically or face-down – the cadaver remaining in this position. During life, the pumping of blood by the heart ensures a relatively even distribution around the blood vessels of the human body. Once this mechanism has ended only the force of gravity acts upon the blood. As with any mass, the blood settles at the lowest point of the body and causes edema or swelling to occur; this reaction is called lividity.

If an individual dies vertically (as in a hanging) the blood will settle in the legs and pool at the feet. The pressure will be greatest as the weight of the blood pushes down. This causes the blood vessels and tissues in the feet to engorge to their greatest elastic capacity and hold the greatest volume of blood possible. This effect occurs right up the legs although to a lesser extent than the feet and is also notable at the waist.

The blood which remains in the torso attempts to move to a lower position due to gravity, and as the blood in the waist (which cannot move down due to the legs being full) causes the penis, consisting of erectile tissue, to fill with blood and expand. This is the death erection. As long as the body remains with the genitalia in this position the effect will continue. Eventually, as the body stiffens over time, blood coagulation will make the erection become permanent.

In popular culture

• Kevin Smith's first movie Clerks features a scene which shows a death erection, although this is the result of someone dying with an erection, not the aforementioned pooling.

See also necrophilia.