Dirty Sext (Accidental Stepbrother Book 3)

I received a dirty text, it said...Sext Me. I know who it's from, but he doesn't have a clue that he's texting the wrong number. Tomorrow I can worry about the truth. Number one - I’m not a student. Number two - I’m his professor. And the most important issue...Number three - I'm soon-to-be his stepsister.