I agree with everyone that a physical problem is probably the cause. However, I know from experience ....yes, you Rudy!.... that jealousy can also cause it. Whenever I've paid too much attention to one of my other kitties and grouched at Rudy's rough housing, as his "person," Rudy let's me know he's mad by (1) not giving me kisses when asked, and (2) peeing on any of my boyfriend's clothes that are on the floor. Hence, Bob's nickname for him ... Rudely!