This isn't gonna be a long one.
What I was wearing. Black padded bra, black tank top, short jean shorts (not that this is important to the story, but no panties). But, essentially, my cleavage was on point and I don't mind eyes leering when I'm out running errands.
Anyway, coming back to my car, I noticed a dude in the passenger seat of his car, pants pushed down and tugging away. Not unattractive, but not stunning either, and an average sized erection.
His window was open even. I just awkwardly said, "Hello".
He just looked at me, didn't say a word. I put my stuff in my car turned back around and stated, "Don't touch them."
Then, I lifted my shirt and bra and let my boobs fall out in through his window and pressed myself into his car so for some privacy as I looked around for onlookers. I heard him grunt and then backed away to see him shooting ropes of cum on himself. I put my bra and shirt back down and got in my car and came home.
And that was my first encounter with a public masturbator.