the largest amount of sputum comes up when I do the laying on my back using the Aerobika. However that does not mean you will have the same experience. I have chronic mucoid Pseudo which can produce a lot of mucus and I have had Bronchiectasis for a long time. Why the large amount will not come up unless I lay on my back using the Aerobika (and then sit up to cough it up multiple times) I do not know. And my Pulmo has no explantion about the reason either. It is hard to compare our vastly different bodies. But on the other hand someone posted this suggested technique from her pulmo and it has helped more than I can say. We have to find a good balance of sharing and realizing how different we can be. Try it and see if it helps.