We have had our male cat for almost 6 years and he has been neutered since 6 months old. For the past 8 months or so, he has been spraying the fence in the backyard as well as several of the plants, etc. He has two litter boxes in the house. He backs into something, lifts his tail very high and sprays. He is now lifting his tail in the house in the same manner and I am afraid he will spray inside. Any help to stop this would be greatly appreciated.