Milk mixers are available online at Amazon.com and from Hammacher Schlemmer. The product goes by two different names. On Amazon.com, it is the Moo Mixer Supreme, but at Hammacher Schlemmer, it is known as the Messless Chocolate Milk Mixing Mug.
This milk mixer features a small button on the handle, which when pressed, mixes the chocolate milk or hot cocoa mix right in the mug. This is a child-friendly product and comes with a spill-resistant lid and cow themed design. The motor runs on two AA-batteries, and it thoroughly mixes chocolate powder or syrup. It is dishwasher safe, can be used to mix hot or cold beverages and holds 16 ounces.