Himself, is not a children's term. adult children might use to to refer to their Da, but (in my experience) not use himself to his face-then he was Da(h)..

my mother would say, Himself when talking about my Da.
(my mother (and Nana) disliked the pronouns he and she and would rant when we used them at home:
'and who the hell is she?.. she is nobody but a cat's mother.. use her name!'
so rather than saying 'he went and bought himself a car' about my father, she's say 'Himself went a bought a car'.

I don't know why she ranted about he/she... but other adults (in and from ireland) took the same tone when we were kids.. so its either a dublin thing, or irish thing.. (what do you say rubrick?)