If you have a kid of your own who reads, where does he/she sit when reading at home? Everywhere and anywhere is the answer.
They lay on the floor, they slouch on a sofa or sit upside down on a sofa hanging over the arm.
They don’t of their own volition sit at a desk or table. Why? Because, duh, it’s not comfortable!
If you want kids to read and lose themselves in a story, or use iPads or other devices naturally as they would at home, then give them beanbags, floor pads, soft bucket seats and sofas. If they need a desk, just make it comfy to sit at.