Task: Question Answering
Input (English): Context: I was having a restless night anyway , so my pajama bottoms were sliding down and getting all off kilter and tangled . I scooched my butt up to reposition my pants - and threw my back out . This incident is right up there with the time I slammed the car door on my head , and it trails only a tad behind the time I gave myself a bloody nose by pulling up my pants in a public bathroom . Probably the most memorable incident was when I was a young teenager , and I was returning an overflowing armful of books to the public library . 
Question: What area of the body did the narrator hurt this time ?
Output (English): backside.