Ah, yes, sorry. [Whoops, have a sheepish tone at that before he pauses to consider the question.]

The last and only time I saw him switch was when I accidentally hurt him when I was bandaging his wrists. Kuzuryuu mentioned something similar happening when they were in a room together- I suppose pain might be a trigger. Of course that leads to a great many problems, we can hardly go hurting him just to get him to change.

I keep hoping I'll remember something about him... maybe then there will be some clue.