Advice as to what Snaking Head means

Hi there, I have had my horse for 4 years, bought wild from Wales at 2.5 yrs. During that time she has always done a behaviour that I strongly feel is dominance, but I am not experienced enough to confirm this, which is why I want to ask you. Having googled and stuff without success. I am hoping someone here would know what it is. It is not headshaking - as I had a horse with this.
What happens is that when you put the pressure on her loose to move away from you, she snakes her head at you. Its a sort of twisting and sometimes she does it and doesn't look at you. She does it on the lunge too. Again not all the time. I am assuming its a sort of "don't tell me what to do" or "I'm having the last word" She always does as she is told, but does do this snaking - is it a protest?
I'd describe her as a confident and dominant horse, she is almost always head honcho out in the field. When she isn't and someone challenges her, she usually has a fight with that horse.
Has anyone else had this and what do you make of it?

Yes, head snaking is a sign of displeasure, as well as trying to show dominance.

Unless it just chases away the flies or stretches the neck. Lol! My qh shakes her head at flies BADLY (I ended up getting long nose net and short fly mask with ears, otherwise it's impossible to ride her).

OP, does she pin ears/bare teeth at you when she does it? If not I'd think it's more of annoyance. If yes, then she tries to establish herself as boss. On lunge I'd just give a shake or 2 of the lead to remind her to stay focused and if doesn't work just ask her to change the direction (to keep her mind busy).

What would someone do to correct this behavior? My 9 year old Qtr/Arab gelding does this as well.

Changing direction immediately will change her attitude. But it often takes at least 3 changes of direction and maybe more before the horse figures out that her action results in your reaction. Consistancy is a must. Some horses don't like to canter on the lunge because of the pull on the joints.

Josey,
YOur assessment is right, from what I can tell from your description. If she does what you ask and is not trouble, then I guess you can let her express her feelings. But you can do as Saddlebag suggested and work the feeling out of her.

My four year old does this on the line and under saddle. It's pure attitude. I growl at her and she is slowly getting the idea it's not ok.

I am bringing her along more slowly than I normally would. She has a temper the size of Texas and I not going to risk ruining her. I don't back down but I recognize when to stop the session. We are both stubborn as heck so it's a big concession for me to not push.

My high-spirited QH did this her WHOLE life-- at the start of every ride. I called it her way of cussing. (She really loved being ridden, she just had to "swear" before going out.) If you let her have her say, it will probably get milder, or even disappear. The worst thing to do, and the hardest, I believe, would be to try to change who she is.

Thank you all for your great advice. I do get the impression he has a small attitude problem, but he is coming along very nicely.

Thank you so much everyone! I really appreciate
Your views. Very reassuring actually :)
It's been making me so curious for ages
And when you google it, all you get is stuff
On headshaking, which I know it isnt. I think
:)