Remember you asked for this. Here's the fairy sex ed post
Partially cross posting from twitter but without nearly as much of a character limit, if you recognize it no you don't <3
Vaguely nsft under the cut; this is intended to be a psuedoscientific exploration of speculative biology and fairy reproduction, please don't reply to this post with highly sexual commentary (jokes are fine lmao) because this is primarily a family friendly blog.
Prefix:
Starting this off by saying that, while this post is going to focus on reproduction via their physical forms, fairies are essentially made of magic and can, for the most part, manipulate those forms at will. Think of these like the default settings of physical manifestation.
Also it's worth noting that while I'm for the most part using human biology terms, fairies themselves probably have ridiculously whimsical names for all these organs that have existed for billions of years, but this isn't a language post.
This is not meant to be a full comprehensive medical guide to the complexities of gender in fairy culture, nor will it cover every possible variation of default physical forms. This is your middle school "where do babies come from" level of documentation. The terms "male" and "female" are used to describe fairies as they are "assigned" at birth, however, please don't take this to mean trans and nonbinary fairies don't exist, they definitely do.
Anatomy:
When manifesting physical forms, fairies develop traits based on the dominant species of the world they will primarily engage with, in this case, humans. (1) This leads to the development of secondary sex characteristics such as breast tissue and facial hair. While these traits have evolved over millennia spent alongside humans, they are still derived from magic, and can not be used to qualify fairies as mammals.
Fairies are an oviviparous species, meaning an embryo will develop within a fertilized egg and depend on that egg for nutrients, but will hatch inside the parent's body and result in a live birth. (2)
Females produce eggs and lay them via an ovipositor. Males produce sperm via internal testes used to fertilize eggs as they pass through the birth canal towards the brood pouch via penetration by ovipositor. The birth canal and ovipositor are both is self lubricating when aroused to assist the transfer of eggs, and the internal pelvic muscular structure in male fairies is designed to pull the eggs as deep as possible to increase chances of fertilization within the brood pouch.
The urinary and reproductive systems are completely separate because they keep canonically arguing about leaving the toilet seat up and while I'm only loosely respectful of canon I can also do whatever I want forever. The female urethra exists behind the ovipositor while the male urethra is connected to a non-reproductively functional penis. Ovipositors tend to be slightly larger than penises, and female fairies tend to be slightly larger than males in general, but this is primarily dependent on the individuals
Both the ovipositor and penis have an abundance of nerve endings and experience arousal, though male ejaculation is entirely internal.
The brood pouch is functionally a uterus in human terms, however, as the developing embryo derives nutrients from the egg and has no need to fully attach, the brood pouch does not have a lining and, sorry everyone, men don't get periods, nobody has to get periods in my world because I'm a benevolent god.
Fairies experience 3 types of puberty, "pooferty(3)" "pasta puberty(4)" and sexual maturation. The first two of these involve developmental milestones and magic-hormone interactions, so they are best set to the wayside for a different post, though I will note here that most secondary sex characteristics will develop in manifest forms at the end stages of pasta puberty. The sexual maturation stage of puberty is the only stage in which hormone production is more of an active cause than magic.
Females may begin laying eggs during this time, and nocturnal depositing is very common in teenagers and nothing to be ashamed of, it's a very normal experience to wake up to the occasional egg or two. At the end of class you'll receive a pamphlet with a section on proper disposal spells.
Males may experience abdominal cramping during third puberty, as their brood pouch swells slightly to accommodate possible eggs, this is not cyclical in the way human periods are, and once they've had their last growth spurt and the pouch settles in its more spacious form, any residual cramping should subside. Until then, the pamphlets offered at the end of class will also have a section on magical pain relief.
Reproduction:
A female fairy can lay between 1-5 eggs, which are semi-gelatinous in texture and range from .5"-1" (1.27-2.54cm) in size. Egg coloration comes in a myriad of pastels, but despite some outdated theories, the coloration of the egg indicates nothing about the potential appearance of the baby.
As previously stated, when the female lays her egg/s inside the male they are fertilized internally. The male will carry the fertilized egg/s in his brood pouch, but the embryo will remain inside the egg through development, using it as a source of magical nutrients
If an egg laid inside a partner in whatever orifice is not successfully fertilized, it dissolves within a matter of 6-12 hours. Birth control looks a lot different for fairies because it's essentially exclusive to a morning after spell to forcibly dissolve the eggs anyway.
After a 3 month gestation period, the embryo will have fully absorbed the nutrients from the egg and will essentially have "eaten" it's way out, which will trigger the father going into labor and, theoretically, delivering the baby via birth canal.
In practice however, magical c-sections(5) were the go-to long before the baby ban. Seriously this has been the preferred method for millennia. Only holier-than-tho crunchy granola weirdos get superior about non-magically assisted delivery.
Citations:
In s3ep12 Abracatastrophy we learn that fairies take on godparenting duties and physical traits of the earths dominant species.
the college by where i live is finally doing... some sort of survey on iron cross blister beetles which is probably good bc "we know nothing about its biology, including... immature stages" can you fucking Imagine. 'yes if a horse eats one of these bugs it will die. yes it lives on organic (meaning no pesticides to kill them) spinach around harvest time and does sometimes get harvested. no we dont know what the fucking babies look like' you Huh???