You were the step sister of Tom Riddle, and you were his student, so he was your step brother and your DADA Professor, but you both were in a secret relationship, you both know it wasn't right at all, you are seventeen and him 22..
Right now you were straddling his lap because he was sitting on a couch, and you both were kissing passionately, and his hands were on you back and he whisper in the kiss.
"This isn't right.."
You both keep kissing and you response is.
"This isn't right at all.."
You both keep kissing, with your arms around his neck and his hands on you back and he whisper against your lips again.
"You are my step sister and student and you are seventeen.."
And you answer.
"Then kiss me until im eighteen.."
And you go both go back to kissing, his hands on your back, your hands now on his shoulders.