Mix the batter just a little thicker than usual, make sure you get all the lumps out. This is a great chance for the kids to participate.
Step 2: The setup
Pour some of the batter into a ziplock bag. Don't worry about spills because I rarely get it all in without slopping some down the side. Once the bag is closed, you can wash the outside with water to reduce further mess. Tip the bag upside down and snip about 3 mm off of one corner of the bag. The size of the hole is dependent on the thickness of the batter and is something you need to experiment with. If you find the hole is a little big, you can tape it closed and cut the other corner.