In simple layman's terms, Madam Pomfrey explained how a girl would go about becoming pregnant. The man would insert his object aka Slot A into Slot B of a woman. She clearly emphasized the importance of slot B being properly prepared prior to Slot A being inserted therein. There is a always small tearing of the Hymen if properly done would not be not very painful with only minimal blood if at all. Otherwise, if done wrong, it would rather be rather painful often accompanied by bleeding.
After that rather embarrassing explanation of the reproductive system, the third-year girl's faces were impossibly bright red with sheer mortification as they all unanimously wished the ground could swallow them whole. The only small consolation to the entire humiliating situation is that the boys had it worse, they were stuck with Professor Slughorn who enlightened them on the path toward manhood.
Madam Pomfrey clears her throat loudly at seeing the numerous embarrassed gazes stuck to the stone floor of the classroom. "Now the most important lesson to remember is how to take the necessary measures in order not to become pregnant. There are potions, but most are for abortions or sterilization if a woman no longer wishes to bear children. These cannot be used as a daily anti-conception method without serious side effects."
Madam Pomfrey solemnly eyes despite their obvious discomfort. "What can be used daily without any side effects is an anti-conception spell, which must be cast each time one is intimate. I know that several of you will protest and argue that it is entirely the male's duty and responsibly to do so, but it is not the male who will end up pregnant for nine months!"
The girls blink at the sternness in Madam Pomfrey's gaze, before she firmly says, "Now I want you all to carefully watch me show you the movements and cast the spell. This is the one spell that I want all of you to practice repeatedly until I'm certain all of you, young ladies have memorized it."
With clear reluctance, the girls watch Madam Pomfrey slowly show them the wand work for the spell, thrice. "Nullus Praegnatio!" Madam Pomfrey cried out as a faint mist-like glow emerges from the wand and falls onto the caster.
"REMEMBER that this spell must be uttered PRIOR to being intimate and not AFTER," Madam Pomfrey determinedly emphasized. "Now go on, I want to see everyone try until I am satisfied."
It felt like it was the longest practice ever as every single girl practiced the spell over and over again. It was rather astonishing that even the thickest among them had mastered the spell by the fourth try. It would seem that mortification was quite infective when mastering this particular spell. But more importantly, it was a spell that none of the girls would ever forget even if they wanted to.
Madam Pomfrey finally nods in satisfaction and says, "Excellent work. Now, it was not my intention to frighten all of you. There are indeed charmed items to be worn to prevent conception if one is regularly intimate with a partner to ensure that there is no conception. However, said items tend to be rather costly, and as such this simple spell tends to be far more practical for personal use."
Madam Pomfrey paused and glanced at the girls, who were all staring at the floor like Rowan past Madam Pomfrey and at the wall. "Now then are there any questions?" Madam Pomfrey solemnly asked.
None of the girls raise their hands, but Prefect Pizarro does. "Yes, Miss Pizarro?" Madam Pomfrey said as a unanimous groan can be heard in the room as Prefect Pizarro snorts at the third-year girl's reaction.
"I know that the girls are too embarrassed to ask at present, but much like the female Prefect at my own lesson, I shall ask the question on their behalf," Prefect Pizarro said with some satisfaction. "What if there are issues with monthly cycles? Or strange symptoms in their loins such as itching or a painful skin sore?"
"Excellent question, Prefect Pizarro!" Madam Pomfrey exclaimed as the girls sunk into their seats vowing to never step foot into this classroom again!
"Whatever the situation, please come to me," Madam Pomfrey pointedly said. "We can take care of the problem and ensure that all young ladies remain perfectly healthy and safe."
All the girls are unable to stifle a groan as Prefect Pizzaro raises her hand again and says, "And what about maintaining physical cleanliness not including using a deodorant and acne?"
Madam Pomfrey beams as the girls look like they are about to cry. "It's important to have a clean body and not to go too many days without an actual shower or bath. Cleaning charms can only do so much."
"As for using a deodorant or maintaining one's face clear of acne, I do not believe I need to cover those grounds as much as I am sure friends or female relatives have already handed over said intended products," Madam Pomfrey plainly stated. "However, if there is ever a time when these mentioned personal products are out of stock, the infirmary does have a stock should the need arise."
Seeing that the girls are ready to melt and disappear into the stone floor, Madam Pomfrey finally says, "Young ladies, we are done, and you are all dismissed." Instantly the girls scramble to their feet and flee as far away as they can from the matron of the infirmary.
Prefect Pizzaro smirks and says, "It's so much more fun to be on this side of things. Good evening, Matron Pomfrey," before striding away.
Matron Pomfrey ruefully shakes her head and glances down at the time. Dinner was still twenty minutes away; she'd finished with plenty of time. And after dinner, she would meet with the third-year female Hufflepuff, while Professor Flitwick would do so for the third-year Hufflepuff boys, and tomorrow for the Gryffindor boys, and his own Ravenclaw's.
Seeing that she still had time for a quick cuppa, Madam Pomfrey makes her way to the staffroom. The staffroom is a long, paneled room full of old mismatched chairs that had seen better days. Pleasantly chatting over a steaming teapot of tea and gingersnaps are two witches; Professor Pomona Sprout, a squat little witch with wry and dirt-covered clothes, while the other, Madam Hooch, a witch with short, frazzled hair and yellow-like eyes debate the winner of the next Quidditch league match between the Wimbourne Wasps in their next upcoming Quidditch match against the Montrose Magpipes.
The two women smile in the direction of Madam Pomfrey, who takes a seat next to them and serves herself a cup of tea. Madam Hooch a fan of the Wasps and proud to call herself, "A Stinger," argued, "Really Pomona, the Magpipes have no chance of beating the Wasps in the upcoming match!"
Professor Sprout tugs on her patched hat over her flyaway hair and says, "Rolonda, though the Wasps do indeed have beater Ludo Bagman on the team. We must remember that the Montrose Magpipes have won the League Cup 32 times and the European Championships, twice! And they presently have some of the best chasers around. I do believe that even if the Wasps seeker catches the snitch, the Wasps will still lose the match against the Magpipes!"
The two witches glare at each other, while Madam Pomfrey wryly says, "Pomona, I'd wager that your Hufflepuffs and the rest of the students would be shocked to find out how feisty you are in regard to your precious Magpipes."
Professor Sprouts faintly blushes and says, "Well, we Magpipes must flock together against the Stingers!"
Madam Hooch lets out a huff and crosses her arms over her chest. Her sharp yellow eyes dart over to the matron of the infirmary. "So, how were the Slytherin girls, Poppy?"
"Perfectly embarrassed," Madam Pomfrey chuckled.
"The poor lasses," Professor Sprout muttered with pity. "My poor badgers will be later tonight. But I suppose it's a small mercy that it will be you doing so, Poppy. And for which I am forever eternally grateful to you, my dear."
Madam Hooch shudders in horror, "I still recall ours with Matron Wally in that sharp librarian tone of hers explaining about the birds and the bees." All three women shiver and despite being in some years apart, they'd all had the misfortune of knowing Matron Wally.
"Thank goodness for small mercies," Madam Pomfrey muttered under her breath.
The three women quickly change the subject as the door to the staff room opens and the younger Professor Zephyros, the Divination teacher enters the staff room. With distant, red-tinged eyes and in a dreamy voice, says, "Good Evening ladies. Might I have a cup of tea before dinner?"
"Have a seat, Ariel," Professor Sprout kindly gestured, while Madam Hooch made a face. She didn't Professor Ariel Zephyros takes a seat next to Madam Pomfrey, who carefully eyes the young man. "Ariel Zephyros, I would hate to remind you that I am obliged to report any illegal use of herbs to the board members of Hogwarts," Madam Pomfrey sternly said.
Professor Zephyros shakes his oily head causing the strings of his stringy hair to whip around him. "They are medicinal herbs, Matron, I can assure you that I have a prescription," Professor Zephyros stammered.
Madam Pomfrey gives the younger Divination Professor a look of disbelief as Madam Hooch lets out a loud snort. Failing to notice the displeased expressions of the three witches, Professor Zephyros begins to ramble, "I can't wait to see what my Tessomancy reading will tell me today! Did you know that tea reading is a practice that is believed widely to have been from the orient to Europe? It is-."
All three women quickly down their tea and make inaudible excuses about heading to dinner. Professor Zephyros is clearly lost somewhere on the horizon and fails to notice them leave in a hurry. In fact, he would completely forget about them as he solely concentrated on drinking his tea and reading his tea leaves. It was a triangle, an unforeseen legacy.