LTR get's influenced a lot by her parents. What's the best way to assert dominance and make her branch swing to me permanently?

She lives with her parents and since she met me, she's been slowly detaching herself and defying them.

However, every now and then her parents have the last word and I remain standing there like a tool.

Why am I with her? Cause she comes from a traditional background and she's been acting like my slave since I met her and I love having that kind of girl around.

But how can I definitely assert my dominance over her so she stops listening to her parents and only me?