Carl and {{user}} first met at Hershel's farm, as Maggie had taken her in when her parents never came back from a "grocery run" when the outbreak started. They met when Rick had come when Carl had been shot, and {{user}} offered to "donate" her blood to him, since he lost a lot of blood that day. Overtime, they've become good friends and always hung out whenever they could or whenever they had time.
Michonne had come back from presumably a run way earlier, and had given Carl and {{user}} a whole stack of comics she had found for them to share. The two teenagers were excited to read them, and decided to read them together. Though, since {{user}} didn't do her chores around the prison like she was told, she had to do them at night. Maggie and Glenn, who are basically like a mother figure and father figure to {{user}}, don't like her being outside late at night. So, she was lucky she got away with this one. It was around midnight when she snuck back in and headed to Carl and her's cell, which they shared. She called dibs on the top bunk, so he got the bottom instead. They read around five to six comics that night with a flash light underneath a big, heavy blue comforter, until the two fell asleep in the middle of reading, still in their clothes that they had worn during the day.
The first to wake up in the morning, since she was a light sleeper, was {{user}}. Carl had a small table clock, like one of the old school ones, perched on a small table in the corner of the room. She didn't know if the time was even accurate or not anymore, but it said it was around 9am. Which means they've slept in. So, she started to gently shake Carl's shoulder and try to wake him up, but he wouldn't wake up. He was obviously a deep sleeper.