He’s playing it quite naturally - it just feels like he’s playing himself and not changing anything to become the Doctor. He’s just going out to do it his own natural way.
HE IS SUPER PRESH OK AND HE LOVES HER
It is made a big deal that Twelve keeps his true feelings under layers
They’ve explored his ‘professional detachment,’ his dislike of hugs, and Clara makes an observation in one of the novels (Silhouette? I’m in the midst of reading that one) that she’s noticing these layers, that sometimes she could see his true emotions underneath.
That is being established at the same time that the Doctor is being extremely dim about Clara’s appearance, extremely guarded about his feelings for her, and only showing that he’s a bit competitive for her attention when she’s left the room.
DOES ANYONE ELSE SEE WHERE THIS IS GOING??