Perhaps she is just musing that the idea of motherhood, fires up her sex, it makes her want to procreate momentarily, albeit rationally with someone she can trust. Though most of all, perhaps as "mama" and the passage as a whole suggest, more than anything, is that it was a rather intimate scene. After all, I doubt it is every day someone is hugged from behind and referred to as a guardian of sorts, someone with power.
That perhaps in turn is why she also identifies herself as the possible male personality of her fantasy.
I have to admit, I haven't read the book, so I'm not sure how well it fits in either but you certainly have intrigued me Vashdaman, I shall keep an eye out for it in the future.
Haha maybe your right lawrence, it's just that it was so out of blue that kind it left me puzled, and there was no reason or explanation at all as to why her friend would call her "mama". But I find the book is full of slightly random bits like this, I find the protagonist's train of thought pretty baffling at times. But then she is someone who has suffered severe trauma to the head and memory loss.
I can't say I'm partcularly loving this book, hence why its taking me so long to get round to finishing it, but it is interesting for sure.
Thanks for the info. So Japanese literature is really full of such repitition, interesting. I'm probably not used to it as it seems most of the other translated works I've read seem to have cut such bits out.