In this thread
viewtopic.php?f=6&t=824, I mentioned something about hoops on the floors, walls, and ceilings that bondage ropes or chains could be connected to so that you can tighten the restraint connected to the various limbs.
I would like to suggest that a player can anchor and/or lock any object they can hold/turn/manipulate to any other ridged surface, like a magnet. Much like the dildos can attach to the fuckmachine (only also be able to move and lock down the fuckmachine), with any wall/floor/ceiling or non-moving surface. (suction cup dildo on a glass door would be a good starting point from a developer perspective) This would not only work so that the player can put these chain/rope loops anywhere they like in the scene and give for custom Bondage situations (it's the main reason I'm thinking of it) but also let you lock things like boxes, desks, and chairs down for sexual positions or even just decorations.
A simpler plan might be to just give the player the ability to lock down or turn off physics on any physics enabled object and allow the rope/chain object to be tied to anything including the collars/bracelets/nooses that can be put on the center of the girls limbs and at their joints... or perhaps even a bondage rope dress.