The focus of this warm-up is proper use of the diaphragm when singing. Have students separate each syllable completely that is marked staccato. Not connecting will force the stomach muscles to work.
This warm-up is for older students. Part 2 is written in bass clef for your changed, changing, or lower voices. As with most partner songs, each part is sung independently at first, then combined. (from Music K-8, Vol. 14, No. 5)