I have known this financial planner for two years. She is very caring and gives honest advice on insurance matters.
The problem is she likes to discuss work matters in her car, which I am sometimes uncomfortable about.
I've told her many times to meet in a cafe, but she is reluctant to do so. Sometimes, she dresses sexily and that turns me on.
Which is more uncomfortable for you - the fact that the meetings are in the car, or the way you feel when you notice her style of dressing?
Why does she want to meet in the car? Is it because the meetings are quick? Is she concerned about not getting a place to park, or does not want to pay for parking? It may help you to find out from her.
If you think her reasons are not good enough, you have little option other than to assert yourself. If she tries to convince you to meet in the car, avoid giving excuses and just tell her that you prefer to meet at a different place. She might want to know why this "sudden" change, as you've always gone with her choice. You will have to think of a good reason, but make sure it is not a lie.
Now, if the real source of your discomfort is her dressing style, meeting at a café may not make you any more comfortable. If you find that you're still distracted by her clothes, divert your attention. Look elsewhere or focus on her face as she talks. Or, you can just focus on the task that you are there for.
It is hard to qualify dressing "sexily" as different people have different ideas about that. What seems sexy to you may not be so to her.
She has every right to dress as she chooses. If her dressing is over the top, surely she would have been told so at her place of work, if they want to maintain a professional image. Just remember that as you have a professional relationship, you have to remain and behave professionally with her.