Use a high-powered blender or a food processor to blend the frozen bananas, stopping to scrape down the sides of the blender as needed. Add milk or yogurt by the tablespoon if needed to get the blender going.

After the bananas are the consistency of ice cream (you may need to throw in an ice cube at a time to make it icier), stir (don't blend) in the graham crackers, chocolate chips, and marshmallows.

Scoop into bowls, drizzle with a little chocolate sauce, and serve immediately, and enjoy!