Either you’d be kinking your neck very far (and still have to bend your knees to fit), or you’d be in a position that I don’t consider lying. Reclining, maybe? Leaning back?
In order to be lying down, I’d say your back has to be in contact with the horizontal surface
If you can lay down comfortably in your bath, you’re either very short or your bathtub is huge
Lie flat? Sure. But lie with your head propped up? That’s normal.
Either you’d be kinking your neck very far (and still have to bend your knees to fit), or you’d be in a position that I don’t consider lying. Reclining, maybe? Leaning back?
In order to be lying down, I’d say your back has to be in contact with the horizontal surface