You've asked your favourite student to stay behind after class to let her know that you won't pass her in this course unless she does something for you...by letting you into her pussy raw and filling it with a load of baby making cum. She's shocked, but knows that passing this course with a high mark will allow her to continue her PHD; she accepts and you both head to her house where she strips for you and admits that blackmail is a turn on for her and she can't wait for your cum to fill her pussy. She fingers it out afterwards, and turned on by the idea of getting pregnant and passing her course she lets you know you can fill her pussy whenever you like.