Diamond excels at being very mean to Tristan. One of her campaigns, aside from trying to starve him out, is to make him feel unwelcome everywhere in the house. If she catches him sleeping somewhere, she will immediately claim it for herself and kick Tris out, even if she's never evidenced any interest in the area before.
For example, the chair in the bedroom. Tris seems to like sleeping with the floofyheads, but since she's discovered him pulling his E.T. stunt, she goes after him if she catches him on the chair.
He'd taken over "my" spot on the bed, but unfortunately, I need it from time to time, so to give him an alternate place to sleep, I put a box down in the living room. He likes boxes.
But this has now created a terrible conflict for poor Tristan. Because he doesn't know if he should "go outside" or "sit in box". Or "eat" or "sit in box".
And to make sure that Diamond stay off his case, I put TWO boxes down and since she can't sit in both them at the same time, one is always available to Tristan. (She's tried scent marking both, Tris is ingoring this subtle little hint.)
The two boxes however are really creating a delima because he absolutely cannot decide if the should "sit in box" or "sit in box".
If only all of our decisions in life were so hard.