A bit reluctantly, but yes.

Ms Nanci glares at you, then mutters something under her breath while she starts to blush. "Oh, what´s that?" You lean in close. "I couldn´t hear that. Can you repeat it?" You start to slide her cock out of your ass, she groans in protest. "Argh, fine! Have your way with me and fuck my cock please. I need to cum!"

You stop teasing her and slam down on her cock again and then start riding it like a madman while almost mauling her tits with your hands. While she tries to keep up a stern front she can´t stop her breathing from picking up and you can feel her rock hard nipples pushing into your hands. "Told you it would feel good huh?"

Before she can answer you kiss her as aggressively as you can, taking her by surprise. While she tries to gain the upper hand in the ensuing tongue wrestling she´s distracted by her impending orgasm. She screams into your mouth as she cums in your ass. You, ofcourse, knew this since her twitching cock gave you all the warning you needed. You amp it up by flexing and un-flexing your ass while riding her cock to really milk everything out of it.

After milking her cock you settle down straddling her lap, her softening cock plopping out of your ass. You cup her face in your hands and give her a gentle kiss which she enjoys. "See, my fun is your fun." She nods and lets you kiss down her sweaty neck to her breasts where you kiss the more mauled areas. "Sorry I got a bit rough."
Finally, you pull back and get off her lap. You walk behind her and before you untie her you pull her head back by the hair and whisper into her ear. "Now before you even think about payback, think about doing this again. But at your place, secretly, we can have lots of fun together. I´ll change the knot so you can undo it yourself, and you´ll go home and cuff yourself to your bed, leaving the front door open." You change the knot and walk over to the classroom door, turning back briefly to see a stunned Ms Nanci staring at you. "I´ll be watching to make sure you do what you´re told Ms Nanci. See you tonight." And you swagger off with a cum filled and sore ass but your pride through the roof.