This pose is too hard
More often than not that’s what I think (this pose is too hard) when the model strikes a pose — especially when the pose presents a lot of foreshortening and an unusual angle, such as lying down. My first charcoal construction marks are not encouraging, but if the pose is long enough I eventually make enough corrections to rescue the drawing from being destined to the trash bin. 40 minutes is our longest pose, so the drawings always have a lot of compromises in accuracy. That’s especially true with the shading since I have time to do very minimal shading during the pose and finish it from memory later. What I don’t remember I fake as best I can. Fortunately (for me) there are not photographs to which you can compare the drawings.