Take the candy melts and put them in a microwave-safe bowl. Read the directions on the package and melt.
Put 1 tablespoon of the melted blue candy into one side of the bomb mold that you'll be using. Take the bottom of your spoon and press the chocolate so that it's up the sides of the molds. Make certain to keep it thick during this process, but also even. Repeat this for the rest of the 12 bomb molds.
Once you have those completed, place the molds in the freezer for 5 minutes.
Take the molds out of the freezer after the time has passed and begin to gently tap the sides of the molds. You can then press gently on one side of the chocolate to make it slide out of the mold easier.
Next, you're going to want to start filling in 6 of the molds with other ingredients. Use 1 tablespoon of the hot chocolate mix, 1 teaspoon of sprinkles, and about 8 or so or the mini marshmallows.
Put a plate or a bowl that has a flat bottom in the microwave and heat it until you can feel that the surface is warm to the touch. Take one of your empty chocolate bomb halves and press it onto the flat portion of the plate for about 10 seconds or so. (with the open side of the chocolate bomb down) You're trying to melt the rim of the chocolate cup so that you can join the two halves together.
Once you notice that it's melted, you need to act fast and press the warm edge of your cup to one of the filled cups. This will make this stick together to create the hot cocoa bomb and seal it as well.
Now it's time to drizzle on the remaining light blue candy on the hot cocoa bombs using a fork or piping bag. Do this with the blue first, then the white, and then add on the sprinkles, too.
Once decorated, pop them back into the freezer for about 5 minutes to let them set.