There's nothing better on a hot summer day like a slightly chilled banana milk smoothie.
I enjoy it for a meal so I make a full Vitamix full which is about two and a half quarts.
Easy to make especially if your son does it for you :-)
I put 6 room temperature ripe bananas, maybe more depending on the size, along with 3 frozen bananas in about 3 cups of distilled water. Add more water if you like it thinner.
Blend on high until it becomes a creamy slightly chilled banana milk.
Pour in a couple of quart Ball Jars and enjoy.