Video! =)

There is a series of behind the back elbow wrapping shots called "overlord removes his armor" from the wushu rope dart sets. I really like that name. I'll see if I can find a video of it, Ian does it quite well, and has taught that move out at his crucible classes. I still can't do it.

i find it's great for practice to just try the basic front body movements behind the back i.e. spin it once in the fist, throw it, intercept by raising the other arm into the rope and switching between lefts and rights doing that until it evolves naturally into various btb elbow and shoulder shots, even getting the occasional crown shot in there (looping the rope off the top of your head). Basically, you can do anything behind your back that you can do in front, it's just upside down :p if that makes any sense....play around and figure it out!