When plain cake balls simply are not sweet enough, or you want to inject a surprise into the center of the treats, filling cake pops with icing adds a contrasting flavor and texture. Try injecting vanilla or strawberry icing into chocolate cake balls, or cream cheese icing into carrot cake balls. Once you perfect the technique, you can use it to inject other fillings as well. Chocolate ganache or fruit puree would be delicious as a filling for cake balls.

Attach the decorating tip coupler to the pastry bag. Unscrew the ring, then drop the coupler into the tip of the bag. If you are using a disposable bag, snip off the tip of the bag just below the screw threads on the coupler.

Set the piping tip on the coupler on the outside of the pastry bag. The bag should be caught between the coupler and the bottom edge of the piping tip. Place the ring over the piping tip and screw in place, securing the tip to the coupler and the decorating bag.

Fill the pastry bag halfway full of icing. Twist or fold the loose edges of the pastry bag to close and seal it.

Press the pastry bag gently to squeeze out a little icing. This will eliminate the small air pocket at the end of the piping tip, making the icing flow more smoothly.

Press the piping tip into the center of a cake pop to make a small hole. Squeeze the pastry bag as you slowly remove the piping tip, filling the hole with icing. Set the filled cake pop on a sheet pan and repeat with the remaining cake pops.

Insert a lollipop stick into the center of each cake pop.

Dip the cake pops in melted chocolate or candy coating. This will hold the icing in place and give the cake pops a finished look.