Secrets of Using a Pastry Bag for Icing

Position the desired piping tip securely in the opening of the pastry bag. Using a coupler makes it easy to change tips.
To fill the bag: Fold down the top to create a cuff. Place the pastry bag upright in a tall glass (or use your free hand to support the bag) and use a spatula to fill with your frosting or other filling.
Unfold the cuff and gather and twist the top of the bag. Press down on the filling in the bag to remove any air pockets
To use: With one hand, press the filling down and out while using your other hand to support and guide the bag. When piped design is finished, first release the pressure on the bag, then, lift up while gently twisting the tip.