I ended up getting creative with the frosting.
Enjoy!
I started off by melting both my frosting, and my peanut butter. That's right, peanut butter! You can really melt almost anything to use as frosting. Some other ideas would be marshmallows or candy. You need to make sure you melt it on a low heat otherwise it will burn.
While the frostings were melting I made my mini cupcakes and took them out to cool on a wire rack. If you don't cool your cupcakes they will fall apart when you try to ice them.
Now I dunk each cupcake upside down in either the chocolate or the peanut butter frosting. Sometimes i dunk in both. The reason you melt your frosting is that it ends up with a shinier, cleaner finish than if you were to use a knife to frost. After this step, I coated a few cupcakes with chocolate or rainbow sprinkles. As the frosting is still warm and gooey you can just roll the top of your cupcake in sprinkles to get them to stick. It's also less messy that way.