The anecdotal Thai sex tourism books I read are:
Butterfly (Steven Yang)
Thai Touch (Richard Rubacher)
Butterfly is a must-get
It tells the mongering of an American Chinese freelance photographer who cheong his way around mostly BKK and Pattaya. His book is more like a collection of his own karma sutra ventures hahaha
Thai Touch touches on the general Thai culture - beliefs, superstitions, sex, attitudes towards farangs etc and is a good read overall for those new to Thailand.
Since I had already finished reading, you can get them from me for $5 each. Let me know!