My mare has never had a very flexable neck so the farthest I can get her to turn her head is pretty much just enough to turn a circle nose first. If I ever need to do a tight circle with her I can get her head to my knee but only if I'm pulling her head farely hard. I would like for her to be able to stand still and be able to turn her head around to my knee without feeling like she has to move that direction. I have tried to do this by standing on the ground and slowly asking her to give her head a bit at a time and she will up until a point then she turns a circle.
I don't have much room to ride her but I know I can work on little stuff like this but I'm not sure what the correct way to teach her this would be.
If any of this makes sense I congratulate you.