Set Up the Machine: Place the Ninja SLUSHi on a level counter. If the machine was recently moved, let it rest for two hours before use. Attach the condensation catch, lock the auger in place, set the vessel on the machine, push the bail handle down, and attach the drip tray.
Add the Drink: Pour 64 ounces of cold Dr Pepper into the vessel. For the spiked version, add 60 ounces of Dr Pepper and 4 ounces of spiced rum, keeping the total liquid at 64 ounces. Close the lid.
Choose the Preset: Press the power button. Select SLUSH for regular Dr Pepper or SPIKED SLUSH for the rum version.
Freeze the Slush: Let the machine run until the cycle is complete. The freezing process usually takes about 15 to 60 minutes. Wait for the beep and solid lights before serving.
Serve: Place a cup under the dispenser. Slowly pull the handle to release the Dr Pepper slush, then release the handle to stop. Serve immediately while cold and thick.