Since their night in his chambers, they had seen each other one other time, albeit briefly. She had slipped into his chambers through the fireplace, just like that, and Snape had been stunned at how naturally she abused her power, and at how little he really cared. She had wanted to return his shirt, which she had borrowed, but she was wearing it on her body at the time. He had watched speechlessly as she had taken off first her coat and then the shirt, snuggled up to him in just her bra, and kissed him giddily, only to disappear down the fireplace again shortly afterwards, leaving him alone with his arousal.