Sort of just for practice, because I kinda like drawing male anatomy if you hadn't noticed. But also I reckon Sherlock would definitely be one of those people who ends up with his feet on the pillows, face smooshed against the mattress, and half draped over the edge of the bed by morning.
love it and like you said the anatomy is excellent. but i must admit it is rather nice sleeping like that XD for i sleep like that. you get more arm room and the cool floorboards feel nice in the palm. yep looks like my sleeping positions