Step #1
Pour chocolate syrup into chilled large glass.
Step #2 Gently stir in the milk.
Step #3 Holding the carbonated water about 5 inches from the top of the glass, slowly pour this into the glass until a thick foam comes to the top of the glass.
Step #4 Using a long swizzle stick, stir the mixture once quickly, make sure the foam does not bubble over the glass.