There are sometimes days and times of the day when my embouchure just seems to go completely feeble. Reeds that when things are OK play loud and fat suddenly turn too hard and I can't get any edge and colour into my tone. Sometimes it's just because I'm tired, but something seems to happen to my embouchure that takes all the tension out of it at other times too. I play very loose, never pressuring the reed, have a sound many people tell me is fine, and I like the way I sound, and have been playing reasonably successfully for a long time. I just wonder whether there is some kind of exercise that I could do when this happens to restore my embouchure tension. Ideas appreciated.