If I'm not mistaken, blue milk is the milk that comes from bantha cows. As far as I know, there are no banthas on Earth. But I know a way to get blue milk that actually tastes good

First, you get a glass of regular milk, then you get about half a cup of blueberries and crush them, before you mix the juice with the milk. Blueberry juice has a strong color, so don't get any of it on your clothes (vikings used the juice to color their clothes 1 000 years ago).

You can use sugar for flavor, but it's not necessary.

MTFBWY!