Possible Clues:

• Slow progress by son -- untidy writing results
• Many a prescription?
• Rough hand putting son over edge
• Second slow movement that may be hard to interpret
• Son to go on all fours, showing bad hand
• Slow progress by son — handwriting not very good
• Prescription writing, stereotypically
• Opposite of fine print?
• Many a signature
• School won't make progress very fast with this manoeuvre and how is one expected to read that?