Thanks - looks like a great site here. It does seem like a candle snuffer but seems too small - it would only barely fit over my finger. I guess it would do the job, though.
That's about the best way to describe its shape. However, its too deep a bowl and the airflow would be too restricted (I played trumpet for years). Bugles I've played have always been a little awkward, but the mouthpiece bowls are usually shallower than a trumpet.