I have a dog that's around 2 years old and about 4 and a half months ago, my sister took home a new dog. She used to sleep in a small crate where my dog couldn't see her very well. Now she sleeps in an enormous crate beside my dog's crate. Now whenever my sister takes her dog outside in the morning, my dog will lift his leg up and pee in the other dog's crate. Now mind you, I usually wake up way before my sister (maybe an hour or two), and I take my dog out as soon as I wake up. Even if I took him out twice or didn't give him water for whatever reason, he still pees in the other dog's crate! As far as I know he has no bladder problems, so I'm very concerned about his behavior. He loves the other dog, but he doesn't trust my sister, so I don't know if that information is relevant to the problem or not.