Souma is really susceptible to cracking up, and even memories will put him into laughing fits. But being self-conscious about this, he always tries to hide it. When he does this again at a clothing store his friend works at, the friend asks him why he does that, especially when it's so easy to tell anyway. Later, Shun also repeats the same sentiment...
No way. I thought I was 
doing a good job hiding it.
مستحيل، ظننتُ أنّني كنتُ أبلي
بلاء حسناً في إخفاء ذلك
Seltsam …
Ich dreh mich doch immer extra weg!
Qué raro, con lo bien que lo disimulo.
Qué raro, con lo bien que lo disimulo.
Bizarre,
je pensais pourtant le cacher.
Che strano, pensavo di nasconderlo bene.
Poxa, achei que estivesse
conseguindo disfarçar.
Странно...
Я думал, что хорошо скрываюсь.