Bakers use cake decorating syringes to pipe icing onto a cake or cupcakes for embellishment or to inject filling into cupcakes. When used in decoration, the syringe operates just like a piping bag. It has interchangeable, shaped tips, too. When used to fill cupcakes, the baker inserts the tip into the top of a baked but undecorated cupcake, and injects filling. Then, he decorates the cupcake, obscuring the puncture. Decorating syringes are not medical syringes. Special tools created for this purpose are manufactured and sold in craft shops. Using them is just as straightforward as using a piping bag.
Bake and thoroughly cool the cake or cupcakes to-be-decorated.
Take the syringe, with the plunger pushed all the way down, and stick the tip into the bowl of prepared filling. Pull the plunger back slowly, drawing the filling into the syringe.
Insert the tip of the syringe in the tops of the fully cooled cupcake. Push the syringe until you have piped about two teaspoons of filling into the cupcake. Repeat the process until you have filled all the cupcakes.
Clean the syringe if you only have one, or use a second syringe to pipe icing.
Fit the syringe with the appropriate decorating tip. Take the syringe, with the plunger pushed all the way down, and stick the tip into the bowl of prepared frosting. Pull the plunger back slowly, drawing the frosting into the syringe.
Pipe the frosting onto the cake or cupcakes just as you would with a piping bag. Repeat the process as much as needed to reach the desired level of decoration.