Complex sentence: Gyro is a technique that involves holding the bell in a vertical position, then rotating it clockwise or counterclockwise slowly to create a small vibrating sound; this can also be done horizontally to push the sound outwards.
Split into simpler sentences: Gyro is a handbell technique that involves holding the bell in a vertical position, then rotating it either clockwise or counterclockwise slowly to create a small vibrating sound. This technique can also be done horizontally to push the sound outwards.