How do you handle feeling like a novelty item from a store?

I know - weird question. Let me set the scene for you. When I tell someone (a man) that I am a ballroom/Latin dancer/instructor, I become a novelty item. I have learned to recognize it in their face and tone of voice and change in body stance. Okay, I feel it and it is not a good feeling. They start asking me questions that get personal and leads to questions about sex. Sex with a dancer. Yay. Whatever. I do not want to become a "novelty item" to men (or anyone) because I have Cptsd and Autism. How do you handle this? How do you politely exit the conversation? Leave? Protect yourself?

The way I handle it now is to lie about what I do until I can trust them or just never tell them because I know it won't last. I have never found a good way to cope or deal with this type of situation.
lie about what I do until I can trust them or just never tell them because I know it won't last
I think this is a really good strategy. I used to have a real hard time lying—compulsively told the truth to anyone—which put me in very vulnerable situations and was off-putting to people. My therapist helped me learn that lying is an important skill and form of self-protection. I was accepting other people’s lies and being gullible but not allowing myself to do it and when I did I felt tremendously guilty. So anyway, I think you are handling it well. Eventually you can build up your resilience to being able to reject people and let their disappointment be their own—but even then as a woman sometimes we just don’t want to deal with the tantrum of a rejected man if we don’t have to.
If you don’t want to talk to someone about being a latin dancer? Perhaps just don’t tell people. But:

They start asking me questions that get personal and leads to questions about sex.
This is where I’d throw in my assertive communication skills. We don’t need to be idle passengers in conversations - take charge of the direction of the conversation if it starts becoming uncomfortable.

In most situations, I’d expect people to not get inappropriate about my hobbies. If they’re out of line (for example, if it’s at work), I let them know. Assertively. That gives the best prospect of turning the relationship back towards what I’m more comfortable with.
I agree with @Sideways because you can't really control how people react to you, but you can control how you respond to it. I think because of the nature of PTSD, and the nature of my history, it's not really possible to avoid the "omg! What? How!" aspect of people's reactions. I run a support group for PTSD, so it is more common that strangers who show up know about my Shtuff. I have a little staff blurb that just says "hey, I have PTSD from XYZ."

But if people get inappropriate with me, that's when I shut it down. I am able to tolerate a certain amount of curiosity because that's just human nature and I don't blame people who have never been exposed to these concepts before. But going on and on about sex, or as one person at my old job asked me at random (I had not told her about PTSD or anything, this was at total random), "have you ever been to rehab/are those scars from self-harm???"

Like, none of your business, lady. I am at work.
Dancers & Fighters make better lovers, as a rule, because it’s the same durn thing… bodies working in concert, playing off of each other.

Which isn’t to say some terrible dancers are not amazing in bed. They often are. And vice versa. But? If you see someone with great rhythm, really able to have a “conversation” with the person/people they’re dancing with? Top 10%, is simply expected.

As far as not being a novelty?

You’re really talking about not being desirable/different. There are a couple/few ways to do that, if you wish to bore &/or disgust people into leaving you alone, but ANY kind of desire-ability or difference is going to make people go “Oh???”
I totally agree that if someone starts a conversation that you don't want, working on being assertive helps as you have autonomy.

I'm working on turning things round on them when someone goes into a direction I don't want to go (this really is very much a work in progress!!). Perhaps turn the questions around and say something like "I wonder why you think it's ok to ask that?" If it turns sexual or whatever response that shows the spotlight on their inappropriate conversation?
Or, walk away.

It actually is a really good way of shifting out the rotten apples though. As the right guy will have the right response, so maybe don't lie as you'll know straight away if this is someone on the same wavelength as you or someone who is an idiot?
It actually is a really good way of shifting out the rotten apples though.
This. I've decided to use those kinds of responses as a fast way to weed out people. I may have to deal with them, like in a work setting, but I don't actually have to let them into my life. There's a difference between genuine curiosity and morbid curiosity.
"I wonder why you think it's ok to ask that?"
Also this. The reaction you get often tells you something interesting about the person.

Something to keep in mind is that no one can "make" you be a novelty item or anything else. They can see you that way, that's totally up to them, but you are what you are, no matter what they chose to think.
Something to keep in mind is that no one can "make" you be a novelty item or anything else
My dad did. As soon as I was born. I was his little doll to mess with (not sexually) and dress up. He would sing the Miss America song (from the Miss America pageant on TV) to me every day as a little girl. I was on a stage all dressed up very early. That makes me feel like a novelty item rather than a person. I am from Texas. And man was it bad for girls 40 years ago. Worse now I bet. Anyway... I have just realized this and I am trying to be cognizant of not letting it happen anymore. Although, there may be a better word. I just don't have one. Thank you for your response.
i don't have the social skills nor a memory healthy enough to remember the two stories required to effectively lie: the truth and the lie. i forget my lies far more easily than i remember my truths. my attempts at assertiveness keep betraying my combat training.

the easiest coping for myself is to let my freak flag fly. normal isn't in my birthright. call me whatever mean name floats your boat. i'm already increasing my social distance from you name calling expertise. when they press me for details i don't care to share, i growl at them. literally. i'll bark if i need too. literally. i bite, too. my full denture bite doesn't have the impact of my rotten teeth, but it doesn't take much to scare off a meddling fool. showing my real bitch side has far more impact i've found. my female dog is an excellent teacher. she taught me that a real bitch bites when she needs to but gets back to tail wagging as quick as she can.