She wouldn't let him nap in his bed, so he fell asleep leaning up against it, and in his sleep ending up leaning against her instead.
By the way, I waffled a lot on the use of the word "hell" in this comic, since I don't think Moonforest dwellers believe in a "Hell", though they're probably aware of it as an abstract concept. It seemed to fit Unicorn's feelings best, though. If it bothers you, you can imagine that whatever the characters are actually saying has been "translated" into American English to make it readable. (I'm probably thinking too much about it.)