Haha .....
In one word
MINE
He's very arduously running around your house peeing everywhere going
Mine Mine Mine Mine.......
and when you get up from bed he is taking possession of that too
.... so when you come back into bed
he's telling you
Hey Bud... What the hell you think you doin' This is MY BED
Simple solution
When he does that?
He gets put down on the floor - case closed
The marking is harder with a non fixed male
it's what they do