All this happened, more or less.

By deliberately scrambling a person's visual and tactile senses, it is now possible to give them an "out-of-body" experience.

Two procedures – which are the first to imitate an out-of-body experience artificially – use cameras to fool people into thinking they are standing or sitting somewhere else in a room. They provide the strongest proof yet that people only imagine floating out of their bodies during surgery or near-death experiences.
New Scientist, Aug 23, 2007.

( you tube video explanation... )

Achieving an out of body experience is relatively easy when using auto-training techniques. I've done it many-many times to combat jetlag. It is hard to say why or how the phenomenon works. It might be that my body simply got used to falling asleep after mind-induced "flight simulations" achieved during numerous bedtime exercises. Another explanation would be that the "flight" itself somehow causes sleepiness. Who knows. It looks like, though, that the scientist are getting closer to figuring it out.

The technique they show in the video is very similar to the effect you create in your mind during an auto-training session. That is, you try to invoke or "remember" a perception in your back when it doesn't touch any contiguous surface. Slow swimming is a great preparation for this exercise. The purpose of it is to set up and memorize the feeling of weightlessness in the whole body. You capture the floating sensation, and teach yourself to reproduce it later, practically on demand. Fun stuff.