This was awesome! Now she can begin her life as a perpetually horny "sex kitten", always looking for the next high from the top clients, maybe sometimes competing with the other girls to get them I would bet! It'd just be the center of her life. ^_^

Ok I have an Idea how this could continue,
Its Drugs right? So if it is they wear off after a time and she turns back to a man but he can't lose the thought of experiencing it again so he goes back to the shop and asks the Shopkeeper for more and basically becomes addicted so he makes a deal with the Shopkeeper that he gets the drugs and she "serves" the Shopkeepers customers. And the effects of the drug last always longer and also need more of a dosis to work and he has to manage the double life.