Had an earlier version of this story I wrote in a different post, but decided to re-post here so it didn't get lost in the piles of old threads:

Emily had just turned 14 the day before. Now she found herself bent over a desk at the front of the room in her 8th grade health class. Her shirt was pulled up around her neck, and her small, puffy breasts were hanging over the edge of the desk. Her dress was flipped up and her panties pulled down around her ankles. She was a randomly selected volunteer for that day's experiment: qualitatively and quantitatively assessing the human physiological response to sexual stimuli.

The teacher had his large hand on her ass, spreading her cheeks apart and wiping her asshole with a soft, damp sponge. He said to the class, "I need someone to come up here and administer the stimulation. Who wants to volunteer?" All the boys in the class raised their hands, while the girls looked down at their desks or giggled to themselves, keeping their arms down. "I need a female volunteer, that way Chelsea won't feel so self-conscious. Anna, why don't you come up here and help?"

Anna, 13 years old, a small, shy brunette walked to the front of the class and looked down at her shoes. One of the boys yelled, "Haha, Anna's a lesbo!" The teacher retorted, "We'll not have any outbursts in this class. This is an educational experience and we're doing this for the sake of knowledge." He turned to Anna. "Okay, Anna, start off by applying gentle pressure to her anus and see how she responds." Hesitantly, Anna took her finger and ran it over Emily's asshole. Emily's anal muscles spasmed slightly at the feeling, causing Anna to pull away in surprise. The teacher said, "It's, okay, nothing to be frightened of. Everyone, record that reaction in your notes. Anna, put some of this lubricant on your thumb and press on Emily's anus until you're just able to penetrate it."

As Anna took her lubed thumb and pressed, Emily's face flushed with embarrassment. When Anna's thumb finally entered her asshole, her expression changed to one of shock and surprise, quickly inhaling and emitting a small moan. "Very good Anna," said her teacher, "now I want you to take your free fingers and slowly massage Emily's vulva." Emily She closed her eyes in shame, feeling her pussy quickly growing wetter as Anna executed the command.

"Okay," said the teacher, "I want everyone to come up here and get a close look at what's happening." The other students gathered in close. The teacher grabbed one of Emily's breasts and angled it toward the rest of the students. "Notice how her skin is becoming more flush and the tissue in her breasts is swelling slightly as she becomes more aroused? Henry, come over here and get your face in between Emily's legs. Can you see how the same thing is happening to her genitals? Take a good whiff and see if you can smell the secretions her vagina is producing." Henry, a blonde, slight boy of 13 did as he was told. "Yuck! It smells gross!" He quickly pulled his head back from between Emily's legs. The teacher looked at Henry, amused. "It's an acquired taste, but you'll come to appreciate it. Anna, thanks for your help. There is some hand sanitizer on my desk for you to use." Anna pulled her thumb out of Emily's butt, much to Emily's relief.

"Okay," said the teacher, "now that we've conducted some initial qualitative observations, let's collect some quantitative data.” He produced from his desk a device similar in shape to a rabbit vibrator. “What I have here is a vaginal pressure and moisture sensor with an attached clitoral stimulator.” The teacher spread Emily's pussy lips and inserted the device, aligning the outer branch of the device directly next to her clit. He leaned down next to her ear and said in a consoling voice, “It's okay Emily, I know this is probably a little embarrassing, but just try to relax and enjoy yourself so we can gather some good data.” He stood up and addressed the rest of the class. “The device is connected to the laptop on my desk. We'll use that to control the amount of stimulation applied and it will display the Emily's vaginal contractions on a graph, where we have time on the x-axis and intensity of the contraction on the y-axis.”

He clicked on the computer's control screen and turned the clit vibrator up to 10%. The students alternated between watching the flickers of pleasure and embarrassment on Emily's face and the graph showing a slowly increasing moisture level and only small, occasional vaginal contractions. “Okay,” said the teacher, “what's everyone's hypothesis for what will happen to moisture levels and contraction intensity when I increase the stimulation?” In a bored voice, indicating the students' frustration with such an obvious question, they said in unison, “they'll increase...”

The teacher increased the vibration intensity to 50%. The sudden jolt caused Emily to twitch, and after a few seconds, she closed her eyes and began breathing more heavily. “Very good,” said the teacher, “the graph confirms your hypotheses.” Let's see what happens when we introduce an outside impulse stimulus. He leaned over and whispered something to Tony, the 14 year old boy standing next to him. “Everyone watch the graph as I count down. 3, 2, 1, now.” Tony spanked Emily's ass with an open hand, causing her emit a small moan as her body tensed. “Everyone see that big pulse on the contraction part of the graph? That's from Tony's impulse stimulus. Okay, Tony, please increase the stimulation to 100%.”

Tony clicked on the control application and the room filled with the sound of the vibrator buzzing firmly against Emily's clit. Within seconds, her leg began to shake. The convulsions worked their way up her body until she was completely within the throes of an intense, aura inducing orgasm. “Everyone watch: see how strong the vaginal contractions become during orgasm? This is an indication of female pleasure and can also bring intense pleasure to a male partner during intercourse.” Very few students were in fact watching; most of the male students struggled to hide their erections, while the female students watched with glee as the boys fiddled to position their hard-ons in a less conspicuous manner.

“Alright. Thank you, Emily, you've been a wonderful volunteer. You can go to the bathroom and get cleaned up. Take the rest of the class period the recover and get your notes from someone else to take home for the homework assignment.” Emily pulled the vaginal sensor out with a small queef, which prompted laughter from the rest of the class. She would have blushed if she could have, but her face was already flush from her recent quaking orgasm. She pulled her shirt back on, flipped her skirt down, and walked as quickly as she could from the room.

“For the rest of you still here, I want to you pair up into teams of two, one boy and one girl in each. We're going to recreate what you just saw with Emily, but this time each boy will assess the vaginal contractions of his female partner using his own handy, built-in pressure sensor. To start off, each boy will need an erection. Please pull down your drawers, gentlemen, and let your partner inspect your state of rigidity. Girls, if your partner is not fully erect, apply gentle oral stimulation until he is. Be gentle though, as some of these guys may be quite sensitive and we don't want to cause a premature ejaculation. If he is, go ahead and give his scrotum a lick, just so he doesn't feel left out.”

All the boys stood next to their desks while the girls kneeled in front of them. Some were hesitant to look when their partner produced his penis, but eventually all the girls worked up the courage to touch the mostly hairless cocks in front of them. Most of the boys were still sporting boners that are the product of youth, though a few had lost them out of shy nervousness. The teacher walked around to confirm that each girl was applying proper suction to her partner's penis or was licking his balls until they were ready to move on. “Everyone, raise your hand if your team is ready to move on to the next part of the activity. Okay, it looks like we can go ahead.”

Standing at the front of the room, the teacher said, “Girls, I want to you bend over your desk like you saw Emily doing earlier. Please either pull down your pants or pull your skirts up and remove your panties so your partner has clear access to your vagina. Also, please raise your hand if you've had your first period already.” About two thirds of the girls raised their hands. The teacher went around and handed condoms to their male partners. “The school is short on funding, as always, so only the boys who are with girls at risk of getting pregnant are going to use condoms today.”

“Boys, with the help of your partner, I want you to penetrate your partner's vagina. Do NOT thrust once you get inside. I know you want to, but if you do, I'm sure a good number of you won't last long and you'll miss the point of this experiment—we want you to be able to properly feel the vaginal spasms of the female orgasm when it comes.” The boys awkwardly attempted to enter the girls in front of them, some having an easier time than others, but all eventually finding their way in.

“Girls, once you have your teammate's penis fully inside you, start rubbing yourself however you like in a way that will allow you to achieve orgasm. If you're having difficulty, let me know and I'll do what I can to help.” The group of girls, ranging from 12 to 14 years old, now fully accommodating a range of small, solid penises inside them, reached between their legs and began frigging themselves. Some of the more adventurous girls occasionally groped their partners' smooth balls, while all the boys tried their very best to keep fight the urge to grind against the girl in front of them.

Eventually some of the girls began to moan, and could feel themselves approaching their goal. Stephanie was the first to find herself falling into an orgasm, and as she did, her 13 year old pussy muscles clamped furiously around her partner's cock. Tim had been thinking about baseball and dead penguins when he was jerked back to reality as he was milked hard and fast by Stephanie's pulsing pussy. It was too much for him and he felt a sudden tightness and then a wave of pleasure as he ejaculated deep inside her.

This scene repeated itself again and again until only one team was left, a 12 year old girl and her 13 year old partner. Aimee called the teacher over and explained to him that she'd never orgasmed before and wasn't exactly sure how. “It's okay, not a problem. Let me see if I can help you.” The teacher positioned himself under the pair of students. He had also noticed that her partner, Henry, the boy who had been less than thrilled with the smell of pussy, had begun to lose his erection, so he alternated between licking Aimee's clit and tonguing the crease of Henry's balls and the bit of his shaft not completely burried in the young girl's twat. As Henry's erection returned, the teacher focused his entire attention on Aimee's tiny clit and firm, peach fuzz-covered labia, holding her skinny thighs to give himself leverage. The girl squirmed slightly, but eventually found a spot she liked and pressed back against her teacher's probing tongue. Soon enough, she too began to quake and gasped suddenly as her insides began pulsing around Henry's cock. She could feel Henry's cum fill her up while her teacher gradually lessened his attack. She collapsed on her desk and let out a quiet sigh.

The teacher returned to the front of the room and looked out at the boys leaned over their young female partners, hips tightly against their firm asses covered with tiny goose bumps as their cocks wilted and slowly fell out of the tiny, dripping pussies. “Good job all. Class dismissed.”