Your stern professor asks you to stay after class to discuss your recent unsatisfactory marks. After some prodding, you tell her she has been distracting you with her looks and salacious outfits. She chastises you, but can see that even now you're unable to control your attraction, and decides to take pity on you. You'll get some extra credit and help your marks in her class by masturbating together. She gives you a peek under her skirt, showing off panties in your house colors, then strokes her pussy and her voluptuous, round ass. Noticing your obvious arousal, she says she'll change into something more appropriate and play with her wand in front of you - her Hitachi wand, of course. She comes back dressed in her panties, knee socks, heeled boots, and a very tight corset which gives you more than a peek of her huge breasts. After making sure you have just the right view, she starts running the wand over her mound. She warns you that you'll only be allowed to cum when she gives you permission. Things continue to heat up as she teases you, adjusting the speed, making sure you're keeping up with her. Finally relenting, she wriggles out of her panties so you can get a full view of what you'll never be allowed to have. This is all you get, so take advantage of that. As she gets closer to her own climax, she demands you maintain eye contact with her. Finally going over the edge in a riot of moans and quivering, she tells you to cum for her, reminding you what a very good student you are. Maybe there will be more opportunities for extra credit in the future... if you're good to her.