Causal dominance between poly!marauders x fem!reader could look like
Mafia!marauders
Mafia!sirus getting up early to make breakfast for reader and reader only whilst they sleep in because cute bunnies deserve it.
This then causes little wolf boy to wake up earlier than usual which he hates because of the smell. When he gets down to the kitchen he tells mafia!sirus "this looks good" whilst trying to to steal a bit of bacon. This action doesn't go unnotice by mafia!sirus who slaps his hand away and tells mafia!remus "for bunny only" which makes mafia!remus shocked and then go on a rant about why it's not fair and other things.
Only for mafia!sirus to brush it off and tell him maybe he shouldn't of accidentally made princess cry last night, which makes mafia!remus even more grumpy.
Mafia!James on the other hand is listening to the noise whilst in bed with you laughing to himself because this has happened to him before but not because he accidentally made you cry but because mafia!sirus only would do these things for you and look for an excuse as to why he didn't do them for mafia!remus and mafia!James.
<He's a massive pushover for you>
Needless to say after you finally awake and go downstairs to the kitchen you can see mafia!remus eating toast grumply whilst shooting you a glare, you in turn just smile at him before getting into your seat. Mafia!sirus personally greets you with a "hello princess look what I made for you and only you" with a cheeky grin and wink, you just reply with a "thank you handsome" which cause him to blush.
But that stops when you can hear Mafia!remus gagging in the background and saying "ewwww" Mafia!sirus just tells you to ignore it and that he's only jealous, which makes you giggle. Mafia!remus doesn't let that pass by him and tries to tell you to "watch yourself" only for mafia!sirus and mafia!James to shut him down and remind him of last night and how he should put on his big boy pants and leave innocent bunnies alone and stop being a big bad wolf.
You giggle at that whilst mafia!remus grumbles under his breath about a punishment for you giggling at him getting scolded but this'll never make it to real life as mafia!sirus and mafia!James will be quick to defend you but also because deep down he was in the wrong and because this breakfast and you laughing at him getting scolded is the least you can get as payback for last night though he'll never admit it.
This is my first drabble/oneshot so please excuse grammar errors I have no idea if this is causal dominance but imma say it is anyways.
Give me suggestions if you want