Mix together all ingredients with an electric mixer on low speed until fully incorporated. Add more confectioners’ sugar or corn syrup one teaspoon at a time until proper consistency is met. Icing shouldn’t run once piped onto cookie.
Once your icing is the correct consistency, lay a piece of cling wrap on the counter. Pour icing in the middle of the cling wrap.
Wrap the icing in the cling wrap by folding the cling wrap on top of itself. Grab both ends of the cling wrap and swing it like a jump rope. This ensures that the ends of the cling wrap roll up nice and tight.
Take one end of the tightly twisted ends and string it through the cake-decorating bag. I add a coupler first so I can change out the tips as needed but a coupler is not necessary if you are only using one tip. Using a pair of scissors, snip the twisted end and add your cake-decorating tip. You are now ready to decorate. If you will not be decorating right away, store your filled cake-decorating bags with the tips upright and covered in plastic wrap in the refrigerator. I put my bags in a mug or cup so they don’t tip over. Use refrigerated glaze within 1 week.