Possible Clues:

• Write wrong
• Write relevently, e.g.
• Maybe write arbitarily to skip gym before the fifties
• Make a mistake organising the letters for teacher, with pet nearly getting lines
• Mix up letters, fail to deliver with charm?
• Minute is time to get letters out?
• Trigger autocorrect, say
• Blunder as letter writer -- is taken in by male charm
• Write the wrong letters for a word
• Be a letter off?