YOU SAID:
My friends are throwing me a surprise party
INTO JAPANESE
私の友達は私にサプライズパーティーを開いています
BACK INTO ENGLISH
My friend is holding me a surprise party
INTO JAPANESE
私の友人は私にサプライズパーティーを開いています
BACK INTO ENGLISH
My friend is holding me a surprise party
That didn't even make that much sense in English.