“Princess? What happens when a feather falls out?” Twilight asked as she watched her mentor preen her wings. She lay nestled within the large mares forearms having already received a thorough washing of her own. “Does it hurt?”  
“No, my little student. It is just like when a strand of your mane falls out on its own. It is barely felt. “  
The little pony digested the information then watched as Celestia pulled a loose feather from the rest on her wing tip. “What do you do with them?”  
Looking at the rather large feather thoughtfully, the pegicorn then smiled down at her student. “Well there is one thing I like to do with them,” she said matter of factly.  
“What’s that?”  
The Celestial mare pressed the tip of the feather to Twilight’s belly and tickled her.