You try to keep quiet.

You sigh as Kiki's thick cockhead continues pushing at your hole as she gently encourages you to push back. "I know it's a monster, but I lubed you well. It may be uncomfortable or hurt at first, but you won't be damaged. So relax yourself," she whispers in your ear. "Better to have my leaking dick inside than out, right?"

You know she is right, but you aren't sure you can make it fit. It must be over 10 inches long, since it filled your entire crack, and very thick too, since your crack felt stretched while Kiki was nestled there. You relax, and put all of your weight onto your hole. You breathe heavily as you feel yourself parting for her. You get past the comfort zone quickly, and then it hurts. You keep a straight face as you are stretched wider than you can imagine. When it is finally past your tight ring, you slide quickly down the shaft. Your butt presses against her crotch.

"Don't worry, it will pass," she whispers. The rest of the class goes by so slowly. You can feel where her long cock ends inside of you. The pain turns to discomfort near the end of class. She senses you relax a bit. "Now that the pain is gone, doesn't the feeling of my dick inside amaze you? You must feel overfull..." You feel it twitch inside of you.

Then the class is over. She pulls out of you. You pull up your pants and gather your things.