Pour all of the ingredients into the vessel of the Ninja Slushi machine.
Select the slush preset.
Once the machine beeps, dispense and serve immediately.
Notes
Dispense the drink right away. This prevents the slushie from over-churning which will give the drink a buttery texture.
After dispensing all of the drink, run a rinse cycle immediately. To ensure the dairy and sugary soda don't stick to the machine, making it extremely hard to clean, run the rinse cycle as soon as you finish dispensing the drink.
You can replace the heavy cream with half and half for a slightly less creamy texture. This swap can also often prevent that buttery texture if you accidentally over-churn your drink.