Teaching concepts with a song makes it a lot more memorable and can also be a clever "less threatening" way provide correction when needed.
I sing this to the Tune of London Bridges to help introduce and remind students of correct piano posture.
"At the piano sit straight and tall,
Touch the fallboard, don't lean at all (reach out and let knuckles touch fallboard)
Pretend your hand is on a ball
Don't droop your wrist at all.
Piano Posture Song Free Printable
For more tips on teaching correct piano posture in a creative way visit this post