I am practicing my lib buzzing, without a mouthpiece, in an effort to improve tone and relax playing. I have noticed that the most relaxed and easy way to get my lips flapping is with my jaw completely closed. The muscles in the are face completely relaxed and the teeth prevent overblowing. I find that as I open my jaw immeadiately either my lips tense and or I overblow and they don't flap. So I use my tongue and diaphram to control the air flow so that the lips continue to flap. I noticed that using the tongue isn't in very good position to play trumpet, so I use the back of my tongue in the familiar tew position. The coordination isn't that easy, between the diaphragm, tongue and jaw, but it seems to improve the tone and attack very much. Does anyone else use similar lip buzzing techniques? One thing I am wonder is it possible to use the tongue and diaphram to control the frequency of lips flapping and volume without changing the jaw or tensing the lips?