A: With a helpful letter, written with words cut of magazines, that begins "I know what you are doing ..." and offers to keep the matter between the two of you, for a low monthly fee, placed in a garbage bag, and left outside his back door on the 8th of every month.
As a good neighbor, you might also want to advise him of the risks that might occur should payment failed to be made. Such phrases as "I'd hate to see what your pretty little wife does when she watches the video," or "What will your children think of you when you're out on the street" remind your neighbor that you are a valuable friend, who only has his best interests at heart.
But no matter how you word your letter, be sure that the monetary amounts are legible and that the threats are genuine. Other than that, go with your heart. Let your creativity blossom.
Just make sure you don't sign your name. Or include a business card. That's kind of tacky.