Frank and Nikki used to have a definite 'pecking' order, i.e. grooming
order; several times a day, Nikki would walk up to a sleeping Frank and
assume a position in front of his nose, and he would wake up and
immediately start grooming her. It was as if she ordered him to groom
her, but at the same time, he was obviously in charge of the situation.
He was always the unchallenged but gentle ruler of the household.

With Mir and Cal, it's not so cut-and-dry. Neither one will submit
completely to the other one's grooming. Every evening, while I'm reading
in bed, Mir comes and supervises me from the nightstand for a while,
then she comes to bed and settles by my legs. After I turn out the
lights, Caliban comes stomping into the room, jumps into bed and starts
to groom Mir vigorously. She has fallen asleep already, but drags
herself awake after a while to reciprocate. She will *not* be groomed
into submission, even if she's half unconscious already.

Sometimes, Caliban gives my forehead a thorough wash. I guess since I
don't wash him in return, he thinks he's the boss of me. ;)