A duck press is an elaborate, frequently decorative piece of equipment used to flatten a duck carcass, bones and all in order to extract all the juices and marrow. The dish is called Canard la Presse. The liquid is then used for a very flavorful duck sauce. The best presses are manufactured from solid brass and produced in France. A duck press costs upwards of $2000.00
D' Artagnan has a very good description of the device and the dish.
Fantes.com sells a solid brass press. You can also purchase a French-made press at Amazon.com: Duck Press.
If you don't have a duck press: