I feel like this is a photo of their faces after River's just walked in as Clara is making a pass at the Doctor, which is why clara has some fear in her eyes and the Doctor is all "River, I can explain."
That is not how friends kiss/look at each other. That is definitely not how siblings kiss/look at each other, but if that's how you do it in your family, remind me to stay far far away. XD That, my dears, is Whouffle. <3 <3