I am not an expert at all and have no trouble with this pose. But I am doing yoga at home together with my partner who found this pose very difficult. The idea is to move your lungs and breathe by using your abdominal muscles.
I will tell you what was his problem, maybe it will help you. He was really trying to move his belly but somehow ‘kept his breath’. Suck in your stomach muscles towards your spine. With that action your lungs will automatically push out some air. Just keep your mouth open, don’t blow with force, the air will come out automatically when you contract your stomach muscles. The force comes from your stomach muscles, not from your lungs. When you suck in your stomach (mouth open) again and again, you will also automatically inhale passively when your stomach muscles relax in between. Important is that you don’t keep your breath meanwhile and that you really use your stomach muscles. My partner had very weak stomach muscles, so that gave him problems as well. When you really concentrate on sucking in your stomach whenever other exercises requires so, your muscles will definitely strengthen and the pose may get easier.
It also helps to put your hand on your belly, just to know that you are using the right muscles.
Maybe more experienced yogi(ni)s can give some more feedback. Lisa
