Body Centers
Each center contributes to the process of understanding. If the
head center is functioning correctly, it means that space or emptiness
is allowed. What is the significance of space and emptiness? When
there is space in the mind, there is no self-image, you're not
trying to stick to something in particular. You are not trying
to go somewhere. The mind is allowing whatever is there to be
there... The heart center’s contribution has to do with
its central quality, which is the Personal Essence. The contribution
of the Personal Essence is the diving movement, the actual living
of the experience. You not only allow it, you're in the midst
of it, you're one with it. You're really it, you let it happen,
you feel it fully, you sense it fully, you experience it fully,
right? That's the contribution of the heart center. The belly
center has its contribution, which is represented by the self,
the essential self. The contribution of the essential self is
the disidentification, the turning away. When you are truly functioning
in the belly, you are completely present, and being completely
present, you're being yourself. So you are not identified with
the usual activity of trying to get somewhere else. (Diamond Heart
Book 3, pg 74)

Body Centers and attitude
No, it's not a matter of putting attention on any particular
center. It's a certain attitude. In the head center, the correct
attitude is to allow things to happen. In the heart center, the
correct attitude is involvement, participation. In the belly center,
the correct attitude is disidentification. So the awareness itself
is enough. If you're aware that you're not allowing, you might
see why you're not allowing things to happen. If you're aware
that you're not participating, then you might find out what the
resistance is, what the block against the participation is. (Diamond
Heart Book 3, pg 78)

Body Centers and functioning
Yes, usually the belly center has to do with embodiment, with
the capacity to sense oneself. However, the belly center is also
the will center. In a sense, the ultimate function of the will
is to surrender to what happens, surrender to the now. And to
surrender to the now means not to hold onto something. The true
function of the will is complete surrender to what is happening
without holding on. That is will. The essential self, like all
essential aspects, can function in any of the subtle centers.
When one is being the essential self, its location is usually
the heart center. However, when the essential self is functioning
in relation to identifying or disidentifying from any content
of experience, it becomes associated with the belly center. The
essential self is more like a potential for experience, and it
also manifests as the capacity for identification. One of the
results of the capacity for identification is embodiment. Embodying
something means you are identified with what is happening. An
essential state is present. You are embodying it if you are it.
The true self has the capacity to identify with something you
are experiencing, but it doesn't have to. It has a choice; it
has the freedom. When you are the true self, you can become completely
what is there -- one hundred percent. If truth is present, you
are truth -- "I am truth". But the moment something
else arises, you become that. There is no holding on. (Diamond
Heart Book 3, pg 79)