A crescent's horns always point directly away from the Sun. It is a compass, and it is how you catch a fake moon in a painting.

The lit edge faces the Sun, so the line joining the two tips is square to the Sun's direction, which tells you where it has gone below the horizon. Illustrators get this wrong constantly. The classic error is a star drawn inside the crescent's arms, which is precisely where the Moon's own unlit disc is sitting, blocking the view.