Baked cupcakes
Large leaf decorating tube
Pastry bag
White frosting (works better if cold)
Large marshmallows
Miniature marshmallows
Miniature chocolate chips

Insert the large leaf decorating tube into the pastry bag.  Cut off the end to expose the end of the decorating tube. Fill the pastry bag 1/2 to 3/4 of the way full of white frosting.

Using the prepared pastry bag, squeeze frosting onto the top of a cupcake. 
Place a large marshmallow onto the center of a cupcake
Dab a little frosting onto a miniature marshmallow and adhere to the large marshmallow.

You will use a squeeze and pull motion with the pastry bag and leaf decorating tube to create fluffy fur.  Touch the tube against the miniature marshmallow and squeeze and pull away to create fur. Repeat until nose area is covered in icing.  Do the same for the large marshmallow.

Place a miniature chocolate chip into the frosting covering the miniature marshmallow. Place two miniature chocolate chips just above the miniature marshmallows to create eyes.  Make sure the flat side of the chocolate chip is facing outward.

Continue the squeeze and pull motion of the pastry bag to create fur over the large marshmallow and cupcake.