Preheat the oven to 350 degrees and line a cupcake pan with liners. I used black foil liners found here.
Make the cake mix according to the package and fill each liner about 2/3 of the way. Bake according to the package and let cool completely.
Meanwhile, beat the butter until smooth. Add in the powdered sugar and mix. Add in the fluff, heavy cream, the rest of the vanilla, and sugar. Mix until completely smooth. If desired add in the food coloring.
Transfer the frosting to a piping bag fit with a round tip.
Pipe a generous swirl of frosting on each cupcake and pull the bag up at the end to make a “point” on each cupcake.
Refrigerate the cupcakes for at least an hour.
When you’re ready to dip them, heat the milk chocolate until melted. I stir them every 30 seconds and it usually takes me 1 min 30 seconds total.
While the cupcakes are cold, dip each one into the chocolate (letting some of the blue show since it’s a fun color!) then immediately top them with the sprinkles.
You may want to work in batches to keep the cupcakes cool.