My daughter's quirky habit

For some reason, Inara has developed one quirky habit that shocks me every time I see her do it, which is every day. She loves to go to bed with a blanket of some sort so that she can pull it over her head. This seems to be her favorite way to go to sleep. It worried me at first because I didn't want her to suffocate herself. But since she's been doing this for weeks now, it doesn't concern me as much. However, I do think it's one crazy habit.