I use either this chocolate buttercream frosting or homemade vanilla frosting to decorate this easy chocolate cake recipe. I use the following tools to decorate (after my kids choose their design):  Piping bags - I have both reusable and disposable piping bags and use them all the time.  Piping tips and couplers - I recommend a great starter tip and coupler set. However I always make this rosette style cake with a Wilton 1M tip and large coupler.  Pastry Scraper. I use this pastry scraper to make a smooth crumb coat. I love it so much!