YOU SAID:

My friend laughed and I laughed together in japan

INTO JAPANESE

友達が笑って、私も日本で一緒に笑った

BACK INTO ENGLISH

My friends laughed and I laughed with them in Japan

INTO JAPANESE

日本では友達が笑っていたし、私も一緒に笑った

BACK INTO ENGLISH

In Japan my friends were laughing and I was laughing too

INTO JAPANESE

日本では友達が笑っていて、私も笑っていた

BACK INTO ENGLISH

In Japan my friends were laughing and I was laughing too