Lord-Elbrun

Subspace is the term for a mix of (to a greater or lesser degree for every person) endorphins and the like, trance-like state, and extreme levels of either relaxation and/or excitement. It is possible to reach that state without being bound, without pain, and without 'typical' stimuli. Subspace for some is hard to reach, for others easy, and for some can be self-induced under the right circumstances. It isn't limited to BDSM situations, but those tend to be the types of activity most tied to it.

I'm not sure if there is another term for it outside of BDSM type activity.

I've reached Subspace through online chat (not easy), due to having the right mindset, experience with the things written in the text, and relaxation. Now, it hasn't been a LOT of times, but it has happened on occasion. Solo Subspace is risky for a lot of reasons, your brain is working in ways it isn't used to, it's dealing with a super powerful chemical high as well as risky openness to suggestion.

Now, in 'vanilla' life, I've rarely reached it, or helped others reach it. The stimuli aren't as intense usually, 'vanilla' activities to me at least are more mellow and not as demanding. I have heard of similar things from those who do rock climbing, long distance biking/running, extreme athletes. All push their bodies to the point that the endorphins flood their systems, and with that they are pushing further and harder, that can set up all the right conditions for something which could be Subspace.

Hope that helped.