Thanks everyone. I think I'm really going for the route people suggested: "your criticism is appreciated but not asked for. If I need something I'll ask Sensei" This really does 2 things: I speak my mind while being polite, and remind her of her place while not directly burning her ego.
A lot of the time she was telling me to do X Y Z, then Sensei came to the rescue and told me to do A B C. I thought that should remind her that she should not be giving me instructions, but as soon as Sensei leaves my ears get harassed again. It's amusing and frustrating at the same time.
Usually I try to stay as far away from her as possible. But one day she was sitting next to me and was about to salute, I had to shut off my peripheral vision and go directly in the opposite direction to look for another partner. This is horrible etiquette but I had no choice. So I wanna put an end to this.
I'm a 3rd kyu and in our dojo, men wear a hakama at 2nd kyu and women at 3rd kyu. So evidently I'm really hesistant to "talk back" in respect to the "fancy dress".
Frankly I think Aikido is a lifelong lesson and everyone makes mistake from 7th kyu to 4th dan. Our goals should be to help each other train, make mistake and improve together, not to harass.
Now I just wonder, have you encountered something like this personally?
The sex/gender issue is a red herring, in my opinion. Precisely the same issue can arise if all the parties are male. My question concerns the instructor. In my own dojo I can immediately see how individual students do the waza and also how they generally interact with the other students in the dojo. In addition, the instructors actually practise with all the students, including ukemi. There is some discussion, but if I want to stop people talking too much, I tell them straight (you can do this very politely in Japanese). Does your instructor do this?
In addition, there is an assumption here about the value of verbally correcting mistakes. The assumption is that if someone sees another person practising the waza incorrectly, there is an obligation to point this out -- immediately and on the spot. This is clearly the case with the person with whom you are having trouble, but is it the case generally in the dojo? In Japan, such immediate verbal correction is less likely and it is quite possible for someone to be practicing the waza wrongly, but without any correction. As the chief instructor in my dojo, I often see people practising waza incorrectly, but it is quite another matter whether I should tell them so, or leave them to make corrections in their own time and in their own way.
I give seminars occasionally and am constantly surprised at the number of people, including 4th dan and above, who do not practice the waza in the way I have shown. Do they do this because they cannot perceive what I am doing, since their mental map of the waza does not allow for another way of doing it, or because they have already made a mental judgment that their way is better?
Since your aikido practice will be a lifelong activity, I am sure you will be faced with issues like this when you come to instruct classes.