Keep this picture in mind as you practice this week. You do not want to be constantly seeing the maestro's shushing gesture or the palm of his left hand. His "softer, trumpets!" indications are not always this kind and gentle. You can keep him off your case and out of your face with a simple strategy.
Your strategy: a daily generous dose of playing softly! Warning: side effects may include lack of breathing and/or boring playing. If so, take a breath and sing normally. Low decibel work should not mean loss of support or interest. The softer you play, the more you must sustain air and line. The goal is not just being quiet, but playing quiet beautifully.
Develop the skill of controlling a quiet product. Train yourself to be comfortable in pianissimo dynamics.The benefits for you are confidence and favor with audition committees. The soft excerpts are often the deal-breakers in finals. Many wield the big stick, but few can also speak softly.