Possible Clues:

• Sit comfortably, finding feathers under the bench
• Populate the county? Cool it!
• Chair stuffing to stop floating around?
• Get orderly to make a soft seat for a chair, perhaps
• Cease agitation to colonise part of Ireland
• "Take it easy!"
• Stop feathers flying?
• Union: last stage
• ''Not so fast!''
• Perhaps the opposite of 12 across is to become domesticated