Place the milk and matcha in a blender and blend until combined. You can mix them with a whisk in a bowl, just start with a teaspoon of milk first to form a paste with the matcha, and then add the milk gradually a bit at a time. Otherwise, the matcha will be clumpy and not smooth.
Take out two glasses. Pour half of the tea in one glass and half of the tea in the other. Do the same with the matcha milk and the sugar. Mix each glass well with a spoon until the milk, tea and sugar are completely blended. Add half of the boba to one glass and half to the other. Allow the boba to settle to the bottom of the glass. Serve cold.