Possible Clues:

• Bloomer 1 ac and others observed when climbing
• Make a mistake or lose footing aloft
• Mistake, spilling drink over cheek
• Students about to make a blunder
• Pil's error
• Minor lapse
• One boob from the backward students
• It's a mistake not to keep petticoat down!
• It's a mistake to be in the wrong with one's pupils
• A mistake to take backward students