One a week I rehearse with my band. It's two hours long and it's not very high (nothing above high C, which is about what I feel comfortable) but I have to play very loud to even hear myself. Today I was playing and in about half an hour my lips have started to feel tired and not nice. The next half an hour has been very hard, without knowing why, my tone was forced and I was using too much mouthpiece pressure, I kept the playing although I wasn't feeling a bit comfortable. And then, all the sudden, just an hour after begining the rehearsal... something has happened, don't know what, and my air has started to flow nicely through the horn, the mouthpiece pressure was gone and my tone was nice and relaxed. I have really enjoyed playing that last hour even though I was playing top volume and I normally end those rehersals very tired.
Has something like that ever happened to you? It's has been like some kind of weir magic