next time he thinks he wants to sleep in the other room, here is what you do.
You piss all over a paper plate and put it in the freezer. Once it's frozen take the piss plate out of the freezer and remove the paper plate.
What you're left with is a piss puck.
Slide it right under the threshold of the door in the room he's sleeping in and go back to bed.
When he wakes up he'll step in a nice melted puddle of your piss.
This will solve nothing, but I will laugh.