I posted this with the poorly_drawn tag due to the unrealistic/failure anatomy. The tag has a lot of art under it that isn't unappealing aesthetically but rather done improperly in terms of body shape. Please don't remove it again unless there is a decent reason to do so.
If she were to sit up as she's drawn in this image, it would look nothing at all like CLAMP's character designs. She would look like she had an unhealthily elongated torso via unnatural means that was about to fall off without support. Then there's the heavy sink in her lower back and the complete failure at the area where her legs connect to her body. It looks pretty shitty in general!