Pour the mango juice, ice cubes, and 1/2 of the mango (fresh or frozen) into the base of a blender. Blend on high speed until smooth and creamy. Dice the rest of the mango and set aside.
Dip the rim of each glass into some water. Then dip the glass into some tajin to coat.
Add a very small amount of chamoy to the inside of each glass, swirling to coat.
Pour the mango smoothie into each glass and add the fresh diced mango and top with the tamarind straw. Enjoy!
Tips: Authentic Mangonadas are thick enough to let the fresh mango rest on top. Since this recipe uses mango juice combined with 1/2 of a fresh mango, you will have to put the fresh mango in the freezer ahead of time for a thicker texture. Alternatively, you could freeze some of the mango juice into ice cubes.