Find your diaphragm muscles. These are the muscles that help your lungs move air in and out. These muscles are located in a V right below your ribs. There are a couple of easy ways to locate these muscles. Place your hand on the area right under your ribs.
Concentrate on moving your diaphragm muscles. You want to be able to flex them and release them so that you can control them for the flutter technique.
Make sure you have good posture. You want to raise your ribcage while making sure that your arm and neck are relaxed.
Take a deep breath and exhale half of the air in your lungs. To do a flutter, you need to create a vacuum in the area where you diaphragm is.
Hold your breath and make sure that no air can escape through your nose.
Flex and relax your diaphragm muscles to create the flutter. The easiest way to do this is to laugh without breathing. The same movement done in laughing is what makes up the flutter.
Release your breathe when you need to and take another deep breathe to continue doing the flutter.