When my boyfriend Tom and I were doing this in the late 60's he called it cruising. As I always had to be naked for him within ten minutes of getting in the car I never knew if this was expected of me even if we were parked up somewhere secluded but if someone happened by and was interested he always expected me to perform no matter how many. I never refused as I found it most enjoyable. The one thing I would never do was suck strangers cocks.