Perhaps just talking about the body in relation to itself - elbows hit
around waist, hips about 1/2 of total body height, hands hit below hips,
would give enough guidance for the students to move in the right
Proportion is a hard concept, especially as it relates to the body.
Some people wait until middle school to teach
realistic, ideal and distorted proportions. Some people would even
students at this age may not want/desire/able to draw what they
would prefer to draw what they know.