The best I can figure is that it's supposed to be three different uses of the "haa" sound.
The first when she's stretching her neck after reading.
The second I'm guessing that she must have had her nipple rub against her leg when she leaned over (hence the blush) and let out a "haa!" in surprise.
Then the third "haa" from her deciding to have some off-screen solo play.
