It's all about the lines dude!
Two things I really like come together, line drawing and shadows and you know I love shadows. It was a great pose and he is a great model. This was a 30 minute pose and I guess the extra 10 mins beyond our normal 20 min pose made a difference. I had time to refine the hair/beard and his hand.
I have always been fascinated with how artists can reduce forms to the simplest lines and that is my goal this year at the life drawing studio. Also trying to get the hands down because hands have always a real flipping challenge. Here is a great link and the author is right, if you don't get the hand right in a painting or drawing it does stick out "like a sore thumb."
If any of you are thinking about being models here are some Tips for Life Models. Many make the mistake of thinking just being nude is all that's needed. There's a lot more to it and a good model knows that and will help choose poses that are not only comfortable/sustainable but can help maximize the drawing experience for the artists.