First fill a cup with about 200 ml of water or milk or your favorite drink and add a scoop of protein powder. Then start the electric cocktail shaker, it did not spill any water, I was surprised because the water kept spinning also formed a vortex, I repeated the spin twice. But you need to be careful if you add too much water you need to put the lid on to prevent splashing.
I also have a 45oz shaker, if I need to drink a lot I use the electric salt shaker to mix it well before pouring it in.
I do this because the best electric protein shaker mixes the drink better and tastes better than my hand shake.