Go to the library and take out "Miss Manners Guide for the New Milleneum" read the chapter on polite rejection. Great reading! Good information and Good Luck!!
I like to cuddle up on Saturday evenings with a cup of tea and a warm lap blanket and read Miss Manners. And then I write thank you notes for an hour, before retiring to bed promptly at 9pm.
lead them on, and then make them get naked "first" when they do, point and laugh. maybe mail him pieces of dead animals for a few weeks later he'll get the hint