8 XXX : hentaibondage

[Pixiv source](http://www.pixiv.net/member_illust.php?mode=medium&illust_id=57909083) [Bonus image](http://i.imgur.com/VA0fKgY.jpg)
Argh! I hate peril images where I genuinely don't understand the peril. Can anyone guess? I assume from the nooses they are in danger of choking. Are the nooses connected somehow? Probably not. On the left, it goes out of the frame. On the right, it disappears immediately. Are the impalers fixed or going up and down? Are they "held back" somehow by that thread? (Can't see how.) Why is the one chick holding on to the thread for dear life? What happens to the second chick if she lets go? It's just so odd, artist put a ton of time in clearly, but I don't understand the situation they created. Edit; google translating page comments are equally confused.