How is this a metaphor?

Don't listen to Lana O'Donnell. So it's been 20 years since I've read the book, but what was going on in the scene? Were they at a party? Was someone literally coming toward them with a tray of tails? If that's what was happening in the scene, I don't know how that's a metaphor, unless you isolate the word "floated." In that case, of course the tails didn't float, but someone carried them on a tray. Using the imagery of "floating" tails can be metaphoric for how magical and luxurious the tail party was, and how effortless their lives seemed at that moment.