YOU SAID:
i used to sleep with my principal
INTO JAPANESE
私は校長と一緒に寝ていました
BACK INTO ENGLISH
I was sleeping with the principal
INTO JAPANESE
校長先生と寝てた
BACK INTO ENGLISH
I slept with the principal
INTO JAPANESE
校長と寝た
BACK INTO ENGLISH
slept with the principal
INTO JAPANESE
校長と寝た
BACK INTO ENGLISH
slept with the principal
Come on, you can do better than that.