Pour rainbow sprinkles onto a shallow plate. Place a small ramekin, topside down, inside a small bowl wide enough to fit the top of each serving glass, as shown.
Pour the mini-chocolate chips around the ramekin. (If unavailable, add one-half cup chocolate chips directly to the bowl.). Microwave on 50% power just until the chips melt, approximately 2-3 minutes. Check after 90 seconds to determine total microwave time.
Remove from microwave and carefully break up any remaining solid pieces of chocolate with a fork. Dip the tops of each glass into the melted chocolate, and then roll the chocolate-coated edge in the rainbow sprinkles. Roll each glass edge until uniformly coated. Turn upright and set aside to dry.
Add the ice cream, vanilla extract, and milk to a blender and blend until smooth. Add a little additional milk to reach the desired consistency, if desired.
To serve, pour the milkshake into the prepared glasses and top with whipped cream, additional sprinkles, and a maraschino cherry. Enjoy!
Can use full size chocolate chips, but will take a little longer to melt. Use additional chocolate chips if not using a ramekin