Do you ride together in the same car? If not (or on a day you don't) leave something racy, suggestive, spicy in the car for him. A bra tied across the steering wheel at lunch could be fun
Maybe something spicy you want to see him wear or use later on?
just some thoughts,
Pam
ps remind me when I get back from Vegas to give you some titles of books with good ideas on this kind of stuff