I came across this on Flickr and had to show you a use for a spreader bar. They aren't just for keeping a gals legs open, lol.
Attach them to a collar and to the cuffs when bound behind you, and you cant really move much.
It would be good for a bit of posture training too. Now lay her down on the floor and put her into a hogtie. Wouldnt that be just dreamy? I know I've tried it. All I could do was wriggle about on my tummy waiting to get released.