That's pretty much exactly what my dominant ex-boyfriend did to me for a while. We had three known public parking areas and I had to ride in the passenger seat either naked or wearing only a summer dress. Sometimes spontaneously, sometimes by prior arrangement, he let me get grope while masturbating. But always only by one person, never two or more at the same time. I was fingered to orgasm several times by strange men. Loved it, after loosing the hardest level of feeling ashamed.