Charles Graham 
The One Pound Pony Girl [EPUB ebook] 

A lifelong enthusiast of anything horserelated, Gabrielle Aston is intrigued when her new lover offers her the chance to actually become a human pony for him. Thinking it will be a fun and delightfully sexy game to play, it is only after she has “sold” herself for a token pound and been harnessed, corseted, bitted and securely restrained, that Gabrielle learns that he is completely serious and means to transform her into a fully trained ponygirl. At his secluded country farm, strict discipline and training give her no option but to become what he wishes her to be and as her willpower and ability to resist ebbs away, she gradually succumbs to the eroticism of her plight and the thrilling power and control of her Master. As his loving ponygirl, she must serve him willingly and perfectly……….but what if he is not the only one to whom she is required to display her hardwon skills and obedient submission?