I used my regular piping bag and the coupler which meant for an easy transition of tip size. I filled my bag and started with the smallest tip, size 0.
There was an immediate difference between the icing and the chocolate; instead of flowing freely from the piping bag with no pressure applied, the icing took a certain amount of pressure to pipe evenly. I found it worked best by holding the bag above the line I wanted to pipe over, and letting the icing "fall" into place. It held its shape perfectly and looked very nice.
Doing row after row of designs and borders takes a toll on your hand. When piping I use muscles that I don't normally use, it just takes time to strengthen them.