Luftwaffle

Also, I've noticed(sorry for double post) but I've noticed some problems with my tone. That is when I attempt to play a certain note it goes too low than it should, as if something was stuck within the instrument. I've always had this problem, but it seems it's gotten worse due to my rustiness, help?

Hi!, tryouts turned out to be in May, but the problem is I was busy with other clubs so I still didn't get to practice anyway, I just wanted to ask a question about mouthpiece buzzing, what would be the best way to do it? I've found that as I do buzz, I sometimes pinch my lips a little too much any advice? Also, I'm currently working on the major scales, is that a good place to start?

Ok, so I've played trombone 4 years, and I got really tired of it this year, so I quit. Baaad idea, it seems I need to pick up my dusty mouthpiece and welp, I forgot everything! I'm currently having some serious problems, I have try outs in about a month, so I'm not too sure what to do. But any way if any of ya'll could possibly share some websites or something for review of musical and trombone basics I'd greatly appreciate it! tl;dr: I forgot everything musical, have mercy and give me tutorial sites kthxbye.