Rei's become extremely attached to the words "MY" and "MINE" (I was going to call them adjectives, but one or both of them can be pronouns apparently...).
Back to the point, (waylaid by words again!), Rei is asserting where she belongs in the order of things, especially when she proclaims, "MY mommy!"
It seems that she's experiencing some feeling of territorial encroachment by her "little buddy" Kai who seems to receive inordinate amount of attention. We're wondering if her disrupted and disruptive (lack of sleep) the past couple nights is some regressive behaviour to get more mommy time.
So as the parents, we've resolved to give Rei more quality time, one-to-one, with mommy. Next stop? The toilet. Training is about to begin. Sometime. Soon. Later.