the only time my cats have done this is when they are having trouble with their kidneys, bladder or urinary tract. I know this sounds stupid... but cats are smarter than we think. I firmly believe they will act out in this way to 'show' us there is a problem. I suspect the next request may be 'how to get pills into cat's mouth' :) Get one of those plunger type things, you put the pill in the open end and it's a plastic thing that goes in their mouth and saves your fingers from being chomped. Put it far enough back and kitty won't be able to spit it out.
I had to switch my little furry man to a special diet for urinary troubles. He would pee on towels, and rugs... whatever was on the floor. another female cat I had, I didn't notice she had blood in her urine until she pee'd on a newspaper.
So a lot of times this isn't typical defiant cat behavior. Get him to the vet. You will know it if he sprays - he will back up to furniture or whatever, and it smells absolutely horrid - it's not urine... but it's hard to get off furniture and walls. (He shouldn't have urges to spray anyway, since he was neutered before he was fully mature sexually)