The twisted neck routine is totally strange. It just occurred to me, and maybe I’m crazy, but maybe they took turns - stood in for each other sometimes. They look almost alike except one seems to be fatter, or was in one photo. Maybe they figured the twisted neck thing would make it easier to for one to pretend to be the other.
No, the twisted neck is just a trick they learned to make it appear as if they are on intimate terms with the person they are being photographed with.
It’s an affectation.