Slushies (also known by the licensed names Slushee and Icee) are drinks made with flavored pulverized ice. The key distinction between a slushie and other frozen drinks is that the ice never freezes into cubes or blocks; it remains as tiny icy crystals. While most alcohol drink makers requires users to insert ice cubes into the machine to be smashed, shaved or crushed, the slushie machine uses water to create the icy slush from scratch. Small home slushee machines do not have the freezing capabilities of the commercial model. Crushed ice must be inserted to make home drinks, which do not have quite the same icy consistency as the store-bought drinks. The water is placed into the machine and it is turned on to churn. Thirty to 60 minutes are required to make the basic slush, depending on the size of the machine and the size of holding receptacle for the finished product.

Most modern commercial slushie machines are enclosed in a metal cabinet due to the amount of use they receive from self-serve customers, but other models store the icy drink in a glass or plastic container attached to the top of the freezing unit. These are usually dispensed by employees and receive less abuse than the metal models. The machine includes a compressor and a sealed cooling cylinder. Slight amounts of moist slush accumulate on the side of the cylinder, and the auger removes it so additional slush may be made. Some machines that offer two flavors have double the components. The ice drink mixture is continually circulated in the storage area, either by a circular auger or plastic mixing paddles, to retain the texture of the ice mixture at a temperature that does not allow additional freezing or melting. A thermostat on the front or side of the unit allows the temperature to be changed for the perfect mix. Outside temperature and humidity influence the machine performance. While fresh slush is recommended each day, some establishments retain the original mixture for several days and keep the machine in operation through the closed hours.

Early manually-operated machines crushed the ice, after which flavored syrup was added by the operator as the drink was placed into a glass or paper cup. Modern machines add syrup (usually with neon-colored additives) to the ice in the machine so that it dispenses in ready-to-drink form. The syrup is measured into a mixing vat (or bottle) and a preset amount of water is added. This is shaken to mix the two liquids, and the mixture is then poured into an opening at the back or top of the machine. The fluid is taken into the cooling cylinder and the icing begins. Modern machines vend the mixture from an opening on the front of the machine, operated by a valve.