I know the BE Addventure has a famous-ish chapter that delves deeply into this territory. I'm not exactly certain where it is, but I know it begins here;
http://www.bearchive.com/~addventure...020/20000.html , with the Alicia option. It's the most TF-heavy section of the BE I've ever come across.
I don't know exactly where along those branching paths it begins, but there's a section where most/all the characters are turned into sentient boobs with faces. I think there's a portion where one of the female characters adds them onto her chest. It's not exactly what you're looking for, but it's rather close.