When Cas first noticed Rose, he'd tensed, sure that he was about to get a reprimand. His first thought was to fly away, like he had before, but he didn't want to disturb the dogs snuggled up tight against him by disappearing out from under them. He supposed he could take them with him, but that didn't seem ideal either at this stage. That left staying put and accepting whatever punishment his trespass warranted.
One of the dogs looked up at her approach, it's tail wagging furiously - it liked Rose, and dogs were decent judges of human character, he found. That comforted Castiel a little, as did the warmth of her smile and the brightness of her soul.
However, he still couldn't help looking up at her with wide, nervous eyes as she introduced herself. "I know I'm not supposed to be in here," he blurted, seeming to shrink. "I'm sorry. I only wanted to sit with them. The dogs in Perth were so miserable. But these ones are much happier, you should know that at least." The puppy on his lap was dwarfed by the hand he had splayed across her side, seeking comfort from her warmth.