Manually stimulating your girlfriend as she is driving. For guys it's "road head" and so for females it's "road tickle".
George : Hey guess what happened last night ?
Henry: What ?
George: My girlfriend and I were driving to the movies last night and we almost got into an accident because I was giving her a little road tickle.
The act of driving in a vehicle preferably gold in colour. while being fingered by another person. of the sexy type.
someone needs a road tickle