From your description it sounds like these Bonobos are having fun and lots of foreplay, but do they actually go all the way (when they allegedly assume homosexual roles)? Do they? I wonder.

I wouldn't rely too much on popular science books, especially when they describe animal behaviour. Usually these books tend to greatly anthropomorphize animal behaviour in order to appeal to the average human reader and his particular human concerns.

You asked, so let me be explicit as to what "going all the way" means: When 2 male Bonobos "make homosexual love" does an actual *penetration* from behind occurs? (I hope it's clear enough and we'll stop going round and round the bush).

In my opinion the story about the "monkey's doll" is a perfect example for the tendency to anthropomorphize. But as there's no end to arguments about interpretations, let's stick to mere facts: Is there a penetration or there isn't?

So now we know the facts. The Bonobos naturally do "hardcore heterosexul sex" but it never occured to them to do the hardcore homosexual stuff, they are only into endless foreplay in that department.
Well, some people would interpret their "bodily games" as playing, others as affection, and you are entitled of course to iterpret it as "real sex". As I already said, it seems to me pointless to argue about such interpretations.
BTW, "going all the way" is an English idiom with a specific meaning: sexual penetration. For example: 2 teenagers are kissing and hugging etc. for months on end, but sure enough the day will come when one of them (usually the boy) would ask: "When shall we go all the way?"

logical types

http://www.gsu.edu/~wwwlrc/biographies/kanzi.html

and

http://pubpages.unh.edu/~jel/512/chimps/SSR.html