For fifth years, Professor Fah has offered admission to those who are hopeful to take N.E.W.T-level Herbology courses the remaining years of school, and who happen to have a free hour to attend. Absences from their normal schedule would not be accepted.
For sixth and seventh years, Professor Fah has experimented with combining the two years to test new lessons with more dangerous plants. They will be splitting back into their years the second half of the year.
The following letter was delivered to all fifth-year studentsin their common rooms:

Dear Fifth-year Student,
I am pleased about the opportunity to invite you to an experimental Herbology lesson provided for my N.E.W.T.-level students in the advanced years. This lesson provides you with insight into the types of subjects offered for those who earn, at minimum, an Exceeds Expectations on their O.W.Ls.
For this lesson, you will need your dragonhide gloves and goggles for safety as we extract the pus of bubotubers. Potion vials are highly suggested, as a portion of successful extractions will be offered as a reward. This should prove invaluable for those who prepare for the lesson ahead of time by reading up on bubotubers in their textbook, One Thousand Magical Herbs and Fungi.
As a reminder those who attend this class are doing so on their own volition during a free hour and not at the expense of another class. Points will be deducted for any student skipping another class, regardless of how much more tantalizing the subject of Herbology may be.
Professor Fah
Professor Fah looked around the long greenhouse table at the bubotubers in their pots, all bespeckled with protrusions ready to be squeezed and their pus extracted. Each station had a set of tools spread out infront of the pot, a typical place setting of sorts for the class. Among them were tweezers, scalpel-like blades, clamps, sheers, extractors, and larger glass phials. While not all of the tools were used every class, they were always present to test the knowledge of the student fortunate to be in the class.
As the class began to fill, Professor Fah offered a dubious smile to the students. Dubious, because students knew it was a set up. Camellia Fah loved her plants, but it was no secret that she took pleasure in the carelessness of her students. It was also understood that there was always reading or research assignments for homework, even if the professor herself didn't say it directly. A simple 'In the next lesson, we will examine X,' was more than enough information to know what to study.
As the final students entered and the clock on the far side of the greenhouse presented the top of the hour, Professor Fah held up a delicate, gloved hand to signal it was time to begin. "Hello, students, and welcome to our special Herbology class. Today we have some of our fifth year students with us to participate and take note of the lesson in preparation for their O.W.L.s at the end of next term. As a reminder to them, a grade of E, or Exceeds Expectations, is required to take the advanced levels. Those with A's, or Acceptible, marks will be allowed admittance at my discression to fill any empty seats."
Professor Fah gestured toward the bubotuber plant infront of her, the signature smile still on her face. Camellia's appearance was prestine in stark contrast with those witches and wizards who spent hours working with plants. Nary a speck of dirt appeared on her person outside of her gloves and apron. She had paused her lecture for a brief moment to let her explanation sink in before continuing. "Bubotubers are a rather dangerous plant when not handled properly. Gloves and gear on," she instructed with a bit more authority in her voice. Her gloved hands pulled down the goggles over her eyes and gave them a little adjustment before continuing.
"The Bubotuber's pus is a prized ingredient in potion making. It is used in many healing potions and one ointment that I can see many of you would benefit from which can help with acne and pustules on the face. Just a few drops of this pus with a solvent, such as water or a creme, can be applied to the face. Too much, however, can leave boils on the skin. I'm not telling you that one part bubotuber pus to four parts ointment base is a basic formula provided in Witch Weekly a few summers ago, but should you try it, maybe your blotchy red faces will be smooth and clear by Valentine's Day. Or maybe not. " With a quirk of her brown and an sly grin, Professor Fah moved on. Was that the real formula? Surely there were more ingredients! Or maybe there wasn't. She gave them the details needed to find out on their own, but there was also someone impatient or lazy that would answer the unspoken query for the rest of them.
She moved on and began to demonstrate and explain how to extract the pus from the slug-like plants. The distinct smell of petrol began to fill the air, though not enough to affect breathing. Using her tweezers, Professor Fah pulled the sac enough to open it before using the broad size of the tweezers to squeeze the pus into her phials. Gloved fingers would work fine for the extraction, but if the sac was subborn, the pus could shoot out and land on unprotected skin. She left that part out since her demonstration and explanation explicitly instructed the students to use the tweezers or scalpel to create an incision. "For this lesson, I want you all to extract the pus from the bubotuber plant at your station. For those who manage to finish before the end of the lesson, I will allow you to take half a potion phial with you for using in Potions class or... any practice you choose to do before Valentine's Day." With that, she stepped away from her instruction station and began to pace around the long greenhouse table, the smell of petrol filling the air more and more.