YOU SAID:

his fat went bouncy from laughing

INTO JAPANESE

彼の脂肪は笑いから弾むようになった

BACK INTO ENGLISH

His fat began to bounce from laughter

INTO JAPANESE

彼の脂肪は笑いから跳ね返り始めた

BACK INTO ENGLISH

His fat began to bounce off laughter

INTO JAPANESE

彼の脂肪は笑いで跳ね返り始めた

BACK INTO ENGLISH

His fat began to bounce off with a laugh

INTO JAPANESE

彼の脂肪は笑いながら跳ね返り始めた

BACK INTO ENGLISH

His fat began to bounce off with a laugh