You had the test and the results were so disapointing, so your teacher had a talking with you about that and after she asked you to follow her to the room where you were going to have a special lesson from her with special knowledge that you would find nowhere. In that secret room it happened that she turned into someone else with dark nature, coz she made you to take her panties into your mouth to make you silent, gagballed you and taped gaged you and wore a black tight outfit to use you like her toy for fun, she wore also two different masks to make you scared and teased you talking dirty and after stroke your cock with her hands and in the end she licked that through the mask. After you started to be fully hard she took off her outfit and fucked your dick in doggystyle. After she put on her outfit back and said that that lesson is not the last one and you would have more from her. The next day you met her in the corridor and she gave you that hint that it would happen after the lessons again.