Thought I'd recommend this book to you all. I read it about 2 or 3 years ago and it really is an erotic masterpeice. The author is Penny Birch and the story is set in England and basically is about a young girls coming of age in a BDSM sense. It's main thread is pony carting but it is not limited to that alone. Other things tackled are bondage, sexual blackmail, anal play, caning, polygamy and more. It's delightfully English and I recommend you have a box of tissues handy when you read and not to dry your tears either.
Penny Birch is a fairly prolific author and has her own website that is worth a visit. I lent my copy of the book to some friends some time ago and I think I'll need a crow bar to prise it out of their hands.
Greg