as I said on my thread - am almost finished psychology degree I am going to be an Educational and Developmental psych therefore specialising mainly in children and adolescents but one of the things we first look at in a childs behaviour (goes for adults too)
What exactly does their behaviour get them - what need does it fill for them
So the dog trick what does it get him?
some contact, (my H doesn't ask about the dogs (two) nor does he come to visit them)
some control and your attention like you said
he has a reason to call and it gets your attention that he is coming - he is signalling his visit before hand
now the hard part what purpose does this serve him?
gosh should look at the responses i just posted here in relation to myself