Is whiskey.

The first time after he had been home I took whiskey with me to the park, he bloody marked me. I was a bit surprised and wondered what to do. I almost chastised him but when I did he looked like he was about growl. Which doubly surprised me because he showed no aggression any other way anywhere. I wrote somewhere that I appeared as a rock to him. Literally. So he pissed on my leg. There was an issue of sanity for him to mark me. He certainly was not being mean or aggressive doing it. He was gaining and showing trust. Right away I understood this dog was atypical. And I thought he was noble. I eventually taught him to stop marking everything. He is the only dog who ever had this problem lets call it, though it is not clear it is dysfunctional up to then given his upbringing. I don't know what it means to say that but a vet may understand. 

this is what google.com gave me anonymously from searching

why do dogs mark their territory

'google.com search engine in Canada on my computer- see below

Typically, when a dog is marking it is a small amount of urine in several places. These places may be random, or they could be in a favorite spot. Dogs can mark for many reasons; the two most common are to show ownership on what they consider their territory and anxiety.'