I can do shakes using my hand, if I'm feeling good they sound pretty good all the way up to an A, sometimes a B. But I know the way I'm doing these is not good, it beats my lips up when I'm moving the mouthpiece against my lips back and forth to make this happen. So I've been working on lip trills, not only will doing them this way not be so hard on my lips but I also like that New Orleans style sound of doing them this way. I used to not be able to do them at all, now when I'm fresh, I can make from an E to a G sound pretty darn good. Problem is, this only happens when I'm fresh. If I were to try and do one like this way halfway into a set, there's no way. Is there anything that I can work on to target this issue or is it pretty much just an overall strength and endurance issue? Thanks!