Definition: Co-consciousness
Co-consciousness is the ability to communicate with other personalities in "real time," to hear what they think/feel about things, and sometimes to see what they're doing when they have executive control (and you don't).
In some media, MPD/DID has been portrayed at its most extreme end. Someone is one person, and then they are another, and the two people don't talk and they don't know who each other is at all. If they talk at all it's usually through someone else like a therapist. That's a very low degree of co-consciousness and looks more "crazy" (if you ask me).
My experience is mostly different, and if you read the essays section at all or follow the journal there you might start to understand it. For me it's often one of the barriers to believing any of this is actually happen... I don't have an evening personality that is a stripper... my voices never tell me to do anything, they just comment like a little Greek chorus. Okay, a big Greek chorus.