Fill your cup to the top with cubed ice. Then measure out 2oz. of Yakult (or you can use the whole 2.7oz. container for a sweeter, creamier Yakult cocktail) and pour it over the ice.
Measure out 2oz. of soju (¼ cup or two shots) into the glass, and stir the soju and Yakult together.
Either measure or just pour your soda to the top of the glass, then lightly stir everything together (don’t shake or the soda will lose its fizz).