If points in the vicinity of a fixed point tend towards it, it is a stable fixed point. If points in the vicinity instead tend away from it, it is an unstable fixed point.
If a dynamic system is near an unstable fixed point, a small amount of external force may be used to maintain it near that point. If a system maintains an unstable fixed point over a period of time, that is evidence of some hidden mechanism actively maintaining it in that state.
Bad posture is commonly a stable fixed point. Various joints will be jammed fully one way or the other, thus not requiring any oversight to maintain the position. Muscles may be fully relaxed, or worse, fully engaged. It does not require any control system, but it does tend to put excess stress on joints and cause muscle fatigue.
An example of this is standing with your knees locked back.
Similarly good posture -- poise -- is commonly an unstable fixed point. It requires an active control system, but puts little stress on joints, and muscles are only engaged fleetingly to nudge the system back to the fixed point every now and then.
A person with poise appears aware. Maintenance of an unstable fixed point is good evidence of the presence of consciousness.
Similarly things like depression and mania may be instances of a mind without an extra layer of conscious (or habitual) control, and a healthy mind one that has an extra layer of self-awareness modulating its thoughts.
The question then is how to develop this extra layer. I'm pretty sure the answer is conscious attention to the system in question -- listening to it and nudging it ever so slightly back into position when it goes astray... so slightly that it feels more like just noting that it's gone a little wrong than actually applying any "mental force". *Not* imposing a particular pose by force, as this will generally be a stable fixed point. It has to be a conscious feedback loop.
It would be annoying to do this all the time of course, but, handily, once one does it enough it becomes habitual and one can turn one's attention elsewhere. Presumably this involves parts of the brain slowly rewiring themselves into little circuits that mimic your conscious judgement.