He didn't try to stop her from waking up he's was too embarrassed to look at her in the eyes, so he throw the blanket on to cover here eyes... Trust me at that age it's F@cken embarrass to look at that person right in the eyes while you're doing it.
This 1 has the potential to become a long term manga. Romance- School life- Drama. It would be good if this 1 have a sad end like 5 centimeter per second. I would cry for an H manga with good plot.