User blog comment:IamJakuhoRaikoben/Chapter 480: The Northern Gravestone, Review./@comment-24546844-20160405165049/@comment-7418318-20160405191334

While Yukino is the only named char who got that treatment, there's at least one other, probably male, person who also got a chain around their neck behind and to the right of what I think is Hibiki.

With different poses and some even hung up upside-down I think the chains are just for more variety and a bit of added shock value rather than any inuendo.