The Crock-Pot was first introduced to the general public in 1971 as a way for people to cook vegetables, meat and other foods over time periods typically ranging for at least a few hours. Because a meal typically takes a long time to cook in the pot, the flavors of the food have time to marinate and tenderize, and cleanup is generally as simple as taking the the pot out and rinsing it with soap and water.
Set the prime rib on a cutting board. Trim the fat off the rib with a knife, leaving as much as desired for flavor as the rib marinates later.
Take the Crock-Pot's lid off, and set the rib inside the stoneware. Add any desired seasonings to the top of the rib, and put the lid back on, ensuring it does not touch the rib.
Plug the pot into a functioning power outlet, and turn its temperature setting knob, located on the side of the pot, to your desired level; a prime rib will cook evenly for between 4 to 5 hours if you turn it to "High," and it will cook evenly for between 7 to 9 hours if you set the pot to "Low."
Allow the pot to cook your prime rib. Take the lid off carefully when it's ready, ensuring you keep your face away from the steam and bubbling liquids that may come out once the lid is off.
Pick up the rib with tongs, and set it on a plate. Unplug the pot, and allow the rib to cool for a few minutes before serving or eating it.