Thanks. I haven't made it through the whole paper yet, but will.

Trong-jug is slightly different. It is a living practice. One that yogis and Tibetan masters used to animate the dead, travel in an animals body, and, the most messed up part, inhabit someone else's body. Once they took over the target's body, the victims soul would be "realeased" (or kicked out really) to inhabit the bardos or heaven, awaiting to move on or reincarnate again. Used in this sense, it is a practice of immortality because the spiritual body gets a new physical body without having their memory erased or ever having to travel through the bardos or heaven.