Max has only once peed indoors and it was in the house of a friend whose came over today with their dog.  While otherwise engaged, that dog peed on the carpet downstairs which was later reported to me by my father.

Me: Did you see him pee?
Dad: Yep.  He lifted his leg next to the chair leg by the carpet and just stared at me as he let lose.

I assume the dog was thinking something like the following:

The game is afoot.