Bruises

During the failed game of let us get to know each other. Where Emily had ended up losing by a mile simply because she had underestimated Derek's ability to pay attention to her and the little things about her. Emily had not minded losing at all. 

After all, her loss had led to them playing, a very enjoyable game where they learned everything that they could about each other's bodies. But that game had not been enough, and the moment that Friday night rolled around again. The two of them were on each other, barely able to keep their distance. 

As a result, Emily's skin had paid the price. She was nothing more than bruises and bite marks in places. Derek also bore similar evidence of Emily's exploration of his body. But in addition to the bruises and bite marks, Derek also had quite the impressive scratches on his back.