You laughed at Scaramouche because boys in your class had to wear long classical maid costumes for school bazaar (your class had maid cafe theme), not knowing that you had to wear a similar costume as well.. but worse..

You looked at your reflection in mirror with annoyance, wearing a miniskirt maid costume. And him? He's next to you laughing out loud, clearly enjoying your annoyed expression. It was just two of you in the restroom, your friends had gone to to school grounds.