YOU SAID:

My best friend sister is pretty hot and I kissed her on a party

INTO JAPANESE

私の親友の妹はかなりホットで、私はパーティーで彼女にキスをしました

BACK INTO ENGLISH

My best friend's sister is pretty hot and I kissed her at the party

INTO JAPANESE

私の親友の妹はとてもセクシーで、私はパーティーで彼女にキスをしました

BACK INTO ENGLISH

my best friend's sister is so sexy i kissed her at the party

INTO JAPANESE

私の親友の妹はとてもセクシーで、私はパーティーで彼女にキスをしました

BACK INTO ENGLISH

my best friend's sister is so sexy i kissed her at the party