I try and stop her.

You were certainly not expecting this when you accepted (or did you even accept?) the lift. Although it was most certainly arousing, you decided it might be best to try and stop her.
You place your hand on hers and start to remove it from your thigh, but she seems to resist, gripping more firmly onto your body.

"come on now, Don't spoil the fun" she said before finally removing her hand. You tried to just keep quiet, not mention what just happened. But she did not seem like she was done yet.
She started to pull the car over to the side of the road, it was a quiet area, with no pedestrians walking past. With the car now fully stopped, she pressed a button to lock the doors.

She was just looking at you with her deep blue eyes, slowly licking her lips.
"I don't appreciate people stopping my fun sweetie" she explained, still with a hint of friendliness must mostly stern.
You are feeling nervous as she continues to examine you.

"No more resisting, ok?" she said as she leant over towards you placing both her hands on the bulge in your trousers, lightly squeezing, but slowly reaching towards the buttons of your jeans. It seems pretty clear where this is leading, do you resist, or let her do as she pleases?