"I'm submissive by nature but I can also be an opinionated brat. My Dom loves it mostly but my brattishness has become abundant lately and its causing problems. Outsiders wouldn't think I'm subbie at all. Any suggestions how we could fix my brat side? Thnx!"
Well this is an interesting situation. A fairly short question will end up receiving a fairly lengthy answer. Having said that, I will admit up front that I don't have direct experience in dealing with a brat. I will however use my years of experience in life and D/s to at least give you my opinion. Hopefully some of my readers and followers can chime in as well with comments to shed some light and their experience to assist with this answer.
I won't begin to tell you how to directly fix this, but I will tell you what I think makes you act this way and why you do it. At first glance, I want to be a bit harsh...I want to come right out and say that if you act bratty, and you know it, and you know it's causing problems, then just stop acting that way. Seems like a simple answer. Yet, I think there is more to it than that. That very well may be like asking me to quit being Dominant...or like asking a dog to be less dog and act more like a cat. It just isn't in the cards. It's part of who you are and your personality.
I think there are reasons for your behavior. You say you are submissive by nature, which I will not doubt. But, I think you need to feel the Dominance and Control over you. You need to be made to submit. You need to feel a strong Dominance presiding over you. You act out, as in being a brat, to be able to see and feel the Dominance as it is used to rein you back in. Being a Brat is your way of asking for attention, and asking to being Dominated and Controlled. You need that figure to step up and put you in your place. That is what makes you feel like the submissive you need to feel like.
You also stated that your being a brat has been in abundance lately, and I will assume that not only have you been a brat more lately, but have also been more of a brat. Not just pushing a little, but pushing a whole lot. This to me screams of a cry for attention. It is you pushing and testing his position as your Dominant. You need the attention more right now, for whatever reason, and are stepping things up to see if he will step up as well and be who you want and need him to be. Or, maybe this is your way of trying to take things a bit further without actually having to come out and say it. You are raising the bar and seeing if he takes the hint and does what you are wanting. Sounds a bit like topping from the bottom, but that's a whole other post and situation. Or is it? Maybe you are controlling to a degree by being a brat and pushing to get the desired response you need?!?!
So...how do you fix this? I will suggest this...talk, talk and talk some more. Good open honest communication is key to everything. You two need to discuss your situation, why you both feel you are behaving the way you are, and then both discuss his responses to it. This isn't meant to be argumentative at all, just talk it through. It is a way for the two of you to better understand each other, and why you are responding to each other the way you are. It's to help you learn more about each other, to grow as a couple, and ultimately become closer. Then you have to figure out and decide if you can back off, and if he can be the Dominant you need. That doesn't mean he's a bad Dominant or person at all. If your behavior, though, is causing problems, then there is a chance he can't step up, or isn't comfortable, having to hover over and control you that much. Only the two of you can talk this through, look at the reasons behind everything, and then decide where to go from here.
I look forward to all the comments that may point out something I'm missing, or different views of this altogether!