Seems odd that only one hand is bound - better image would be without the chain and it would be a woman simply sleeping. But, the lighting and innate eroticism of the woman is magnificently displayed.
If one goes with a sleeper motif, the contrast between black and white could be highlighted by placing a pillow under the models head. As it stands now her hair bleeds into the background. The classic fetal position does also suggest more submission. So, I do not think that needs to be changed.
However, if bondage or conveying bondage is your aim then maybe both hands above the head.