Headcanon that is most certainly untrue but I adore it:
We haven’t seen Aizawa in his sleeping bag for a while because when Eri was first taken in by UA she was having trouble sleeping. She would have night terrors- no doubt about the trauma she’s experienced.
So Aizawa brought her his sleeping bag and said, “This is what protects me from the rest of the world. When I’m in it, I can sleep anywhere.” He also knows that the feeling of weight on people, especially kids, is really helpful for sleeping, and the fact that she’d literally be wrapped up, she would probably feel safer.
So she took it and that’s what she sleeps in- until Aizawa gets her her own, of course (probably an ugly cat themed one). She hasn’t had a restless night since.
