A proper cupcake should not have a mile-high pile of frosting. That is just bad form and is usually done to hide a shitty or unimpressive cake. But if you should encounter one of these and wish to consume it anyway, what you do is lick/bite off only half of the frosting pile and then proceed to bite into the remaining cake and frosting as normal. Pull back the paper cup as you go, or unwrap it entirely before eating, depending on how messy the cupcake and how badly the paper sticks, carefully holding the bottom of the cake. If the frosting goes all over the sides, pinch the paper toward the middle rather than trying to pull directly from the top. Lick the frosting around the edge of the cupcake in a circle. If all else fails, stick that sucker on a plate or dump it into a bowl, and eat with a fork or spoon. I personally recommend spoon.
All that said, these problems are typical of the grocery store cupcake, which tends to be made entirely of chemistry set ingredients that are not usually considered food. My best advice would be to seek better cupcake. Good luck in your endeavors, whichever path you may choose.