Book/movie differences

I just read the book -- in translation, I confess -- and I was interested to discover that the whole sex club scene was added for the movie. But then again, there were a few details in the book that were omitted from the movie. (At least I don't remember them.) One of these was a scene in which Manu is having her period and is deliberately walking around nude and sitting on things and leaving blood stains everywhere. The other concerned the scene where Manu was giving the guy oral sex and bit it. In the book, she actually vomits all over him while she has it in her mouth. Anybody got any idea why these changes were made?