Not slipping?

[Nuuni]

My voice is mostly good, and I use it all the time, it's very natural for me. Some qualities of it bother me, but they are qualities typical in some cis women.
But now and then, my wookie voice slips out when I am not thinking about it. Or rather, I think I get occasional wookie voice, I can't really tell. I'm not sure how to actually finish erasing that reflex. What do I need to do to get rid of the slips?

[anjaq]

I guess you can hope that after using your new voice exclusively for a long time (watching not to let it slip too often), it becomes second nature and you can keep it up always.
For me, that did not work properly and so I chose surgery, but it seems many manage to get it good without VFS, so it has to be possible.