Wow- reading this thread brought back some memories. I had a copy of this book at one point. I have read it some years ago- and yes, it was quite racy and sexually graphic. It's a shame that this was the only adaptation done for "The Young Indiana Jones Chronicles" written on a young adult (i.e. teenager) level. Of course, the content would push it more towards the adult category, but it does get classified as teen literature mainly for the length, I think- and probably because "The Young Indiana Jones Chronicles" certainly appeals to teenagers.
Of course, there were other novelizations of episodes that weren't quite as fleshed out as this one (pun kinda both unintended and intended.)
There were a series of 8 books based on the series in the US and a few alternate titles in the UK. They are all detailed here