How about the redhead?

Though you have plenty of options to choose from when it comes to girls, your eyes keep getting drawn the the ginger girl up front who first spoke up after you unfroze everyone. She was wearing jeans and a bright green tank top, and she was gripping the edge of her closed notebook in fright. Her seat in the front of the class would also make for a great demonstration to the other girls just what was in store for them today.

"She looks interesting," you say, gesturing to the redhead as you approach her.

"That's a very keen eye you have, sir," Madame Martell says, following you to the front of the class, "Anal Annie here is one of our more popular girls, and for good reason."

"What? Professor Martell, you know that's not who I am!" the redhead pleads, "My name is... is... wait, what's my name? Does anyone else remember my name?"

The other girls in the room get panicked looks on their faces as they realize that none of them can recall the redhead being known as anything other than Anal Annie.

Getting an idea, the newly christened Anal Annie leans over and starts rummaging through the bag next to her chair, "There's got to be something in here with my name on it..."

"Hey, hey!" Madame Martell says, snapping her fingers at the girl, "Stop that! Rummage on your own time, you're on the clock!"

Anal Annie bolts upright and puts her hands back on her desk, looking at them with alien fascination. With a small smirk you say, "Feisty one, isn't she? I'm guessing from the name that her specialty is anal sex."

"Yes, she's one hell of a spitfire," Madame Martell says with a small chuckle, "She's required more discipline to train than most girls I've worked with, but I put up with it because Anal Annie is also one of the biggest buttsluts I've ever met."

"Really now?" you ask, interested in where this is going.

"Her asshole is so sensitive it's practically a second pussy to her" Madame Martell says with pride, "Hell, by now she has a psychological addiction to taking it up her ass. She's mentioned before that if she's gone more than a few hours without a cock shoved up her asshole, it starts feeling like she has ants crawling around in there."

"Wow, that sounds really uncomfortable for her," you say with a grin, "Has anyone used her today?"

"She hasn't had so much as a buttplug up there all day," Madame Martell replies, "She usually keeps something up there to help with the cravings, but I wanted her to be nice and ready for you. But come to think of it, that might explain why she's so irritable right now."

"N-None of that's true..." Anal Annie whimpers, though you can't help but notice that she's now squirming uncomfortably in her seat.

"Are you okay, Anal Annie?" the girl next to her whispers before adding, "Sorry, I... I don't know what else to call you."

Anal Annie doesn't answer vocally, only biting her lip and shaking her head.

"Well I can see she's eager for the butt stuff," you say, "But I'd rather not pay for something sight unseen. Can I inspect her ass for myself?"

"Of course you can," Madame Martell says sweetly, before turning to the ginger girl and barking, "Anal Annie! Stand up and present your asshole to Mr. Birch!"

Anal Annie's green eyes go wide, and she squeaks out, "N-No, I can't...! Please, stop!"

Even as she is protesting though, the girl stands up and starts undoing her pants. She looks down at her hands, trying in vain to get them to stop, but it isn't long before she's turning around and dropping her pants and panties in front of the entire class. One girl even gasps in shock as she sees Anal Annie bend over and spread her butt cheeks for you.

"Very nice," you say, giving the girl's round ass an appreciative glance. Kneeling down, you get a closer look at her light pink anus. It looks rather tight, and you swear that you can see it quivering in front of you in anticipation.

"Please Professor, don't do this..." Anal Annie whimpers. To everyone's shock, including your own, this earns her a hard slap on the ass from Madame Martell. She yelps in pain, but manages to remain in position as per her orders.

"There's more where that came from if you keep this up!" Madame Martell tells her sternly, "Is that clear?"

"Y-Yes ma'am," Anal Annie squeaks.

Curious, you bring a finger up and gently trace it around her asshole. You see her anus tighten up on contact, and Anal Annie lets out a high pitched whine. You do it again, and this time you see her vagina start getting wet from the stimulation.

"MMMmmm, that feels good," Anal Annie says, arching her back and pushing her butt further towards you, "It's never felt that good before... please, just do it one more time."

You oblige her request, and the new buttslut barely stifles a moan as her pussy gets soaked. Whatever the other girl's reactions were to this spectacle, you were too engrossed with what was in front of you to notice.

"Now stick it in, please," she begs, "Just a little bit."

"I wouldn't if I were you," Madame Martell teases, "You might lose that finger with how cock-hungry her ass is right now. Of course, if you're willing to pay for her time, you can help satisfy her craving."

"Please, just one fingertip, please," Anal Annie whimpers again, having lost any semblance of resistance. Her discomfort was both amusing and arousing to you, and you're almost tempted to take her right there. But she was only one of several girls in the room, and it might be more fun to keep her squirming while you browse your other options. Besides, you're eager to see what Madame Martell can come up with for her other students, and eventually another class will probably want this room. Not that it would necessarily be a huge problem to deal with that thanks your Sapphire's power, but it would still be at the very least an annoying hassle you'd rather avoid if you can.