Place the ripe mango chunks in your blender. Add the honey or agave syrup if you prefer extra sweetness.
Pour in the crushed ice. This will give the slushie its frosty, textured appearance.
Burst the ice and mango into a smooth, frozen mixture by blending on high until the texture is thick and slushy. You may need to stop and scrape down the sides occasionally.
If the mixture is too thick to blend easily, add a splash of cold water or juice to help it along, then blend again until well combined.
Once the mixture has a uniform, icy consistency—resembling a thick snow cone—pause the blender.
Scoop the mango ice slushie into chilled glasses. You can garnish with a small mango slice or a sprig of mint if desired.
Enjoy immediately with a spoon or straw for the full textured experience.