YOU SAID:
私は最後の夜あなたのお母さんと寝た
INTO JAPANESE
私は最後の夜あなたのお母さんと寝た
BACK INTO ENGLISH
I slept with your mom last night
INTO JAPANESE
私は昨夜あなたのお母さんと寝ました
BACK INTO ENGLISH
I slept with your mom last night
That didn't even make that much sense in English.