Jace didn't mind at all Mark moving closer to him on the bench, even if it did mean that he brushed against him everytime he moved. It gave him an opportunity to get to look at the other man in a way he normally couldn't - from up close, actually getting to study him. He had to admit Mark was good looking - very good looking, when he was completely honest with himself about it.
He'd known that Mark had seelie blood in him, he'd just never known how much of a glamour he used to mask his appearance. He breathed in lightly when he saw his skin lighten and take on what he could only think of a shimmer. Good looking was going right out the window - a part of him, getting louder by the moment as he looked, was starting to think of Mark as gorgeous and then he heard him start to play.
He didn't know the song but he could almost feel the emotion inside of it as he listened. He couldn't remember the last time he'd just sat and listened to someone else play. He knew he was staring but he couldn't take his eyes off of Mark's face as they sat there, just enjoying the moment, the music washing over him. The act of listening was calming him down in a different way than playing himself did but the effect on his thoughts was the same.
He swallowed and cleared his throat when Mark finished playing, not looking away from him as he spoke. "That was beautiful."