Practice blowing into a mouthpiece with a BERP. The BERP helps teach you to blow into resistance, and become more aware of the resistance within your body and how to avoid it with proper breath support. The BERP will help you fix your sound before it gets amplified by the mouthpiece and instrument.
You can use the BERP to warm up before playing to focus the air going through your instrument, or help through your practice sessions.
Use the BERP with a trumpet, trombone, French Horn, or tuba.