Image by Todd Ehlers via FlickrCatholic school kids of a certain age and time (you know... back when Men were Men, Women were Women, and Children Only Spoke When Spoken To) were scolded on a number of things like:
"Don't Chew the Baby Jesus!" (ie the Host during Holy Communion), "Pull up Your Stockings!", and "Pull Down Your Skirt".
But, also Posture, Posture, Posture! Sit up Straight and Tall. Kneel with Your Back Straight and Not with Your Backside Touching The Pew!
Well, in the end, they were right about posture. But the Good Nuns never taught you these exercises!