Take a real blade and hold it in front of you in a comfortable position. Keep the hand as it is and start to move by walking and moving your body to defend yourself. Switch hands and positions and than do this drill with a practice knife with a friend or more who attack. This is a good way to learn better awareness to your body as you hold a knife. the knife is just a tool. It can cut potatoes and people in the same way. On the other hand even sitting on a sharp branch can be very unpleasent so don’t forget some fear can be good for you.