wisegeek.com
From link:

In the case of the French dish, known in French as canard au sang, or “duck in its blood,” the process for making pressed duck is quite complex. It starts with partially roasting a duck which has been strangled to retain maximum blood volume. Next, the breasts, liver, and thighs of the bird are removed. The liver is chopped and seasoned while the breasts and thighs are roasted separately. Meanwhile, the body of the duck is pressed in a special device called a duck press, which is modeled after a wine press.

Yuk.