Being "in" a coterie means not thinking of yourself as being in a coterie. You might be vaguely aware of it as a "community" or "group of friends," but it's the nature of coteries to be like the water to the fish. And wondering why all those people on the other side of the glass are excluding you from their coterie.

Then there are the fish in the next tank over - now there's a coterie. They're so exclusionary. Those are BAD FISH. Nobody would want to be in their tank.

When there is money (or jobs, publication opportunities, etc.) at stake, everything gets a little more intense. And when you start writing about your coterie's exciting adventures, recording their bons mots, and referring to them by their first names, you've started writing to your coterie - and only them. The people on the other side of the glass have gotten bored and gone home.