Owh, it seems that leaning with your lower chest against your bed improves singing. It helps the sound be a whole lot fuller and louder as well. This makes sense because I remember Marilyn Horne saying at a Master Lesson that actors wear some sort of leather support under their costume to support their diaphragm. I believe that this is the same sort of thing, that is leaning against your bed supports the diaphragm.
In contrast, I tried it without leaning against my bed, even standing up, and I couldn't get the same sound. The sound was not nearly as full, and not as loud.
Now if only there were more beds in places where one would usually sing.