I looked at Henry and slowly reached my left hand behind the curtain. He backed his head up, then cautiously leaned forward to sniff my hand. As he did this, I moved my hand to the left and began rubbing the side of his head. Almost immediately he lifted his neck to be scratched underneathe the sides of his ears and started practically rolling around on the window sill!
So I kept it up! Mia stared at him a moment, then left. I expected Henry to follow, but he didn't. He continued to move all around so I could scratch him in just the right ways. Cora was still in my lap during all of this and was also staring. I'd noticed that her purring had suddenly grown significantly louder at this point.
But then I did a double take. It wasn't Cora's purring that had gotten louder, it was the combination of Cora AND Henry's purring!
HENRY WAS PURRING!
So I continued rubbing his head, neck, back, everything. Then I moved a little closer and moved the curtain back with my right hand. At first he stayed put, but then as my right hand got closer, he bolted.
But still! That was total progress! ^_^