Doing car meets alone could be very risky.
I do them, but I only meet clients with my husband present, so they have to be happy to shag me in front of my husband; as I'm not alone, I've never had any problems, but I would be too afraid to do it alone.
Perhaps hire a man to drive you, and tell the client he can have fun with you in the back with the driver taking no part in it?
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