L'drop
A secret, fast hand-job done in a moving car, usually near Chicago, and usually while the person giving it is trying to stay stealthy.
"He gave me an L'drop in a moving car. I didn't even know it happened until I got out."
"Got an L'drop while the car was moving. I was too distracted to notice."
"She gave me an L'drop in the middle of the expressway. The car almost swerved."