hello tiny clown, thank you for the question!!! for birdie it's mostly north and i actively doing the writing while sola is there throwing in ideas and bits and pieces. so us being "just" two people who actively write the main part makes it a lot easier coordination wise. north and i just kind of write at the same time. sometimes we work on our own paragraphs, sometimes we jump into each other's sentences and start where someone else stopped because the brain wasn't braining. it definitely was a bit of a challenge at first because we weren't used to it but it just kind of happens organically with us.
same with fine line, ami and i just roll with no specific assigned characters or anything. just what comes to mind.
it feels like some sort of natural process for us? just weaving our styles together and it's really fun cause it also motivates to push through the challenging parts that might make you stop for a bit to let it marinade if you were just writing on your own! i def recommend trying it if you happen to have a writer friend and an idea <3