Max, our three year old un-neutered bulldog marked several times in the house today, including right in front of me at the entrance of our bedroom and bathroom. He squatted to do this, not raising his leg. He has never done this before that I know of. I was planning on taking him in for his 3 year physical within the next few weeks, but wife thinks it may be a UTI so I will try to get him in ASAP. Our neighbors do own dogs, but I am not sure if one has a female that is in heat. If there was a female in season, would this potentially be the issue? One other thing is the poor guy had a grape size lump on his rear testicle last Saturday. It was red, but he did not react to any pain. We put some prescription strength Cortisone on it, and it went down within 24 hours. I blamed an insect or ant bite on this, but wonder if it is somehow related.