When Abby-Roo was adopted earlier this year her shark fin-like butt fur, while extraordinarily fluffy, was still rather short (to compare see her early photos here).
As it grew out she developed the habit of getting it soiled. Not the rest of her actual butt fur underneath, but only the ends of her "tail". For hygiene's sake she was subjected to periodic butt baths in an effort to keep her clean. After a few too many, she finally got her first fur trim a few days ago.
In an effort to preserve the rooster tail look she was given graduated layers. Abby-Roo's butt fluff is no longer as feathery as it was previously, but at least now butt baths are no longer necessary. As for regular piggy baths, that's another story.