You're sleepy because the class is so boring you thought

Y:"This class is so boring, let me take a peek at my crush"

You look at xiao and he was staring and smiling at you

Y:"wha..! He looked at me! OMG! wait! Pretend you didn't notice, pretend you didn't notice! Is he still looking?wait"

You peak again and see he's still smiling at you happily