"Happy Birthday, my brilliant student."
Sunset couldn't help but bow her head instinctively. "Thank you, Princess Celestia. But I'm not sure I understand your gift. It's a... pillow?"
The alicorn nodded with a knowing smile. "A pillow, my student. But with a very special inside. Philomena recently molted, leaving behind the feathers I used to fill the pillow."
Pressing her hand to it, Sunset's eyes went wide. Then she brought the pillow to her cheek. "It's... warm." A smile played over her lips. "Like it's been out in the summer sun."
Celestia leaned in to rest her head against her wayward student's. "The down of a phoenix to remind you of your teacher's sun. And a reminder that the homeland that sun shines upon will always welcome you back."
"Of course, it's mostly for winter use. It's downright wretched on a hot summer night."
Aw, that was so pleasant! I really, really like that idea too, with the warm Phoenix feathers.