I have been doing lip slurs for a long time , but I noticed that when I do a trill or wide intervals my jaw moves very fast. low Bb to F above middle C and trills of a minor 3rd or less my jaw moves but not my embouchure. Is this normal or is there some way to correcet this?

sabutin used to say around here, "Try everything, and if it works, do it."

Some people promote the jaw motion, and I hear fine players who show lots of motion. I think what is happening it they are changing mouth volume by using the jaw and that prompts partial change. I think that can all be done tongue only, but I wouldn't be surprised if at low frequencies some jaw would be required. I've heard more than one pro state emphatically that dropping the jaw is necessary for a good second partial. Flexies between first and second partial have my tongue flapping like a piston, so I should check for jaw motion. But you know, it works.

I suggest trying to minimize the jaw motion. There are other changes that do need to happen but jaw motion should be minimal if at all. Trills may be an exception, but still minimal. Watch in a mirror and try to keep it still.

If you need more help, I do Skype lessons specifically to teach correct playing mechanics like this.

<YOUTUBE id="mw0TIDeFVCo">https://www.youtube.com/watch?v=mw0TIDeFVCo</YOUTUBE>

Check it out.