L'drop
A secret hand-job done fast in a car that's moving, usually somewhere near Chicago, and usually while the other person is too busy to care.
"He gave me an L'drop in the back of a moving car. I didn't even know it was happening."
"Got an L'drop in a car that was moving. I was too happy to complain."
"She gave me an L'drop in a moving car. I didn't even realize it until I got home."