To be "north of giddy" - what is this?
"They were to that point just north of giddy, and enjoying a tete-a-tete like nothing he had ever experienced with anyone."
dizzy adjective (FEELING) - definition in the British English Dictionary & Thesaurus - Cambridge Dictionaries Online
"Just north of" means "a little more than".
So, they were a little more than dizzy. Probably from drinking.