Blend the ingredients: Cut the bananas and peaches into chunks and transfer to a high-speed blender. Then add the ice and water and blend for 20-30 seconds, until very smooth and creamy. Give it a taste and add more bananas and peaches as you see fit, in addition to more ice and water until desired texture and temperature is achieved.
Serve: Pour into a glass and enjoy! (You can store this in the fridge, tightly-sealed, for 2 days but the color will darken, so heads up.)