The use of the term 'subspace' is part of BDSM vernacular. With a bit of research, you will find that a great deal has been written about what it feels like, the many ways it is achieved, and the role it plays in each submissive's lifestyle. On the other hand, there isn't a lot written on the state of mind of the dominant (though Daemon does an excellent job in describing the mindset of a sadist).
This is understandable – subspace is almost tangible, a level of consciousness that is a noticeable change in perception and awareness. It has real affects (which vary from person to person), such as an increased tolerance to pain, the sensation of 'floating', a disconnection from the outside world, or even sublime peace.
A dominant's head space is harder to pin down. It is assumed they are thinking up evil plans or planning their next step of cruelty. With their mind filled with the details of running the scene, is there any room for anything else?
Yes.
In broader terms, I use the metaphor of the caged wolf to describe how it feels when that dark desire lies coiled inside me, waiting.
Every so often, I let it out.
This state is rare and most often brought on by a combination of natural hunger, an irresistible opportunity, and a need to test myself. I see the gap between what I want and what she is capable of giving to me at that moment, and distance between the two becomes irrelevant.
I become capable of acts that would normally make me hesitate.
Need becomes a cold fire, and I act in a manner both calculated and instinctual. There are no moments of indecision, no questioning of motive. Those choices have already been made.
All that is left is the feast.
—
And that – that's a small glimpse at how it feels from the other side.