Pastry bags make neat work of many baking tasks that would otherwise transform your kitchen into a blizzard of icing, batter and creams. Often recipes and baking tutorials require you to use a device called a coupler inside your pastry bag, which allows you to switch the tips attached to the bag without emptying its contents first. Luckily, if you aren't using more than one tip or just don't have access to a coupler, there is an easy way to work with the pastry bag alone with the same results.
Drop a piping tip into your pastry bag and push it down as far it can go. Draw a small line on the pastry bag just above the opening of the tip inside the bag. When holding the bag vertically, with the tip on the bottom, the line should be horizontal across the tip.
Take the piping tip out of the bag and cut along the line you drew to create a small hole in the bag. Push the piping tip down into the bag so that the opening of the tip protrudes through the hole in the bag. The tip will not fall out because the hole in the bag is just big enough to allow the piping tip opening to be exposed.
Fold the top of the bag over to create a cuff. Hold the bag up by sliding your hand up under the cuff and holding the bag loosely in your hand.
Fill the pastry bag halfway with the food you want to pipe, then unfold the cuff. Pinch the bag closed just above the food, and twist it shut to secure the closure. Gently work the food down in the bag until it comes through the piping tip opening.
Repeat the same procedure of marking and cutting with any other tips you want to work with using additional bags.
Keep a note of how big you made the hole in the bag for each recipe you prepare so you have the information in the future without having to guess.
Never overfill a pastry bag or the contents will come out the top when you attempt to squeeze it out through the tip.