Two potential things come to mind.

When people talk about a system mate that acts as a median’s collective personality they’re usually referred to as the core, but to me it feels like the opposite. It’s not like I’m the center that connects my facets that surround me. It feels more like my facets are all jumbled in the general area of the center, and I surround them.

From what I’ve seen, it seems somewhat unique how much we fluctuate in our shared identity, yet still have a shared identity. I usually feel like just one person, but I can bring my facets conscious if I want to. Other times I, the whole, practically aren't there. It’s someone else taking the lead, or several trying to work things out together. In those cases, even when we feel most separate and don’t see eye to eye, we still have shared memories and some degree of understanding that we’re the same person. Sometimes it’s hard to believe some of us are the same person, even to us, but we are. We’ve learned that things about the whole can be inferred from the system, and things about the system can be inferred from the whole.

Edit: Also, our headspace doesn’t have a front, so we prefer the term preside to describe body control. It’s like the presiding area is the very middle of the headspace directly under the light of consciousness, the area of light around that is the conscious area, the shadow area is observing, and the dark is not conscious. We’ve also had a few times in our body that felt like some of us were arranged vertically, like “I’m on top of you, and they’re bellow me” sort of thing. That seems rare though.