y/Cute note or object to leave for boyfriend!!?

My y man works on a golf course all day long and we text throughout the day most of the time but i want to do something different that will make him hot when he gets back to his car afterward. Today he isn't working on the course, they get to golf so i want something witty and y to either write out for him or a small object that either way i can stick under the wiper blades of his car or stick somewhere on his car that he will see when he gets back to it. It has to be something half-way discrete so no1 else sees it as they walk by. Any thoughts!!!!