
, now I getz the question. Thanks Lumen.
It looks like it's on its side because of the position we are on the earth.
For example, right now it looks nearly cresent down. If you were on the equator, it would be totally down. If you were on the poles, it would appeare 'vertical' like the typical 'C' shape.
The moon's orbit is pretty much on the same plane as our equator, so its apparent phase's follow the same orientation. As the earth is round (I think it is, or is it flat), your viewing of the moon's angle of tilt would change as you move according to your latitude on the earth.
But the moon's orbit does 'move' like a wobbily disk, which is why, as another example, full moon one day could be overhead, & another lunar cycle it is much closer to the northern horizon. This too will influence its apparent orientation.
As Erick said, what remains constant is the position of the sun, perpendicular to the cresent.
Tricky bugger, eh.