Possible Clues:

• Pets, perhaps, go into reverse
• Move to the rear
• Stop, to think about it
• 'Make room!'
• Don't stand so close, pets!
• Withdraw (from)
• 'Pets, perhaps, go into reverse (4,4)'
• Might pets retreat so?
• Retreat like this to make pets of it
• Perhaps 19 across in reverse