YOU SAID:

I threw a grenade while sitting in a chair next to my friends father

INTO JAPANESE

私の友人の父親の隣の椅子に座りながら手榴弾を投げました

BACK INTO ENGLISH

I threw a grenade while sitting in a chair next to my friend's father

INTO JAPANESE

私は私の友人の父の隣の椅子に座りながら手榴弾を投げました

BACK INTO ENGLISH

I threw a grenade while sitting in a chair next to my friend's father