GamerGoneWild1 It's not hard to learn my high school band director played in the Marching 100 and he had some percussion players come to our school and they taught us how to play Duckmouth.
They are employing the Moeller Stroke. The effectiveness of this method is debatable. Some swear by it, some don't. I don't much care for it, so much wasted movement but that's just my opinion.