Here is the blurb and if you are interested it is available at:
You should be careful what you wish for... Fay is a Christmas fairy who has been with the same family for many years and gets her kicks watching the mother and father have sex on the sofa—although she despairs about their lack of variety. But this year she is replaced by a shiny new angel.
Depressed at being discarded, and no-one with whom to spend Christmas, Fay goes to a paranormal bar on Christmas Eve and sees four handsome (and young!) elves who have just finished their duties for that year. She makes a wish they all ignore how old she is and is delighted when her wish gets granted. So she makes more wishes—naughty wicked ones!