(This analysis concerns yesterday's story.)
Really beautiful shibari has a special hold on me that seems to single itself out from the more general visual arousal of which it's a part. Bondage, non-specifically--shibari, other rope-work, leather, chains, etc.--has a certain power: the idea that a Dominant might restrain me the way the subs in the images I love have been restrained in one way or another always seems to call forth in me a unique arousal in that unlike images that suggest punishment or sex, restraint simply says that the one restrained belongs to the one who restrained her.
Shibari, though, both in the aesthetic appeal of the knots and loops themselves and in the aesthetic appeal of the forms into which the rope shapes the submissive body, adds that layer of objectification that always comes with the aestheticization of the object. That in itself doesn't single out shibari, because of course it's the very same impulse that gives us lacy lingerie (thank goodness!). Shibari is different, I think, because of the extremity of the shaping of the body (as for example in this picture) and because of the range of implications of rope itself--so different from lace. Rope is dominant, masculine even.
Thus, when "Zoe" ponders her crotch-rope, she sees it as the representative of her unnamed "he."