Trombone Buzzing

Many issues can come up while buzzing on the trombone mouthpiece. I've found that if a student has a clear/full buzz on the mouthpiece and can pivot the mouthpiece off of the buzz and keep a "free" buzz moving past the lips, they have a good embouchure/aperture/wind setup.

This video lays out some ways for teachers to identify possible issues keeping a full sound while buzzing and provide tools for identification and practice.