Miguel's no-unsound thesis.
"All bathrooms belong to her."
Me: "All bathrooms in the house belong to the women. If you use a spare is because she lets you."
Buddy: "Bullshit, I have my bathroom and she has her own."
Me: "Does 'your' bathroom have a urinal?"
Buddy: ...
Me: "You are just borrowing it."
PS: The Missus saw the post as I was writing it and she immediately said “don’t even think about installing that thing in my house.” Q.E.D.
This made me laugh out loud, and then contemplate the logistics of putting a urinal in the garage bathroom for Himself. Which, in aid of your point, is not *in* the house!