sitting sideways
For characters sitting with their legs off to one side of the chair or other furniture they are seated on.
Not for tagging the orientation of the chair relative to the viewer or any other pieces of furniture, nor for characters sitting on furniture that doesn't have an orientation.
Not for characters sitting on the floor with with their legs to the side, see yokozuwari.
For characters riding sideways on a horse or broom or bicycle, see sidesaddle.