Severus nodded around a bite of chicken, but after he'd swallowed, he smirked and said, "You do clean up nicely." Then, even if he never thought he would have had the aplomb to do something like this, he winked. Even if his cheeks started to warm not two seconds later.
But the more time he spent with her -- without her telling him off, at least, even if her patience had worn thin more than once -- the more confident he started to feel. Obviously she didn't hate him, the way he'd always thought, even if she probably should have. She was simply too kind for such a thing. Just as she was too kind to embarrass him by playing footsie to an excessive extent in public. He wasn't even sure why he would have thought that, now. Though even in the absence of that faulty assumption, he was still hesitant to conclude that she had been flirting. His confidence could only build so quickly, after all.
"Well, we'll simply have to do both of those more often, then," he added, giving his wineglass a bit of a swirl before taking a sip. "And hope they don't send a search party too soon to look for us, in the case of the latter."