Crawling Badass, Hidden Doormat
The female MC is an action heroine who's pretty badass and it looks like she's got a pretty good shot at completing her quest or mission. What could go wrong? Well the inevitable, whether it's done by a boss, a minion or some weak rando retard, one harassment episode eventually reveals her latent submissiveness. Once she's been down it turns out she must like crawling on the floor, because it usually goes one way from there until she's a complete doormat who by Pavlov reaction submits to, like, randos on the street (maybe even including women if it isn't a Japanese game), snotty boys under 14, stray pets, and probably to the bed bugs in her bedroom though games usually don't show that last part. The story by that point can typically end in two alternatives, failing her mission and becoming a doormat to everyone or passing her mission and becoming a doormat to everyone all the same. Ah, there's nothing like a high-stake story. ¯\_(ツ)_/¯ And crawling is over 75% progress to lying flat on the floor anyway.
Sorority of Horror
In real life sororities can be pretty wild places, with plenty of getting drunk, partying, casual sex, and in some countries they have an increased risk of rape. And can you believe that in some places they even provide housing or study facilities? In adult games sororities are about one thing, prostitution in the barely legal category. So they have to keep the student-to-skeezer pipeline running smoothly and hold to their position as the biggest brothel in town. Really ambitious ones may even try to get a big share, maybe even all female students on their pimping roster. No wonder why uni administrators in adult games always have legal problems.
Hands-on Parenting
Many parents in the real world find sexual education of their children an awkward subject and are happy to leave it to other people. But in a certain type of incest game, they often take the matter in their own hands.
If it's the mother "educating" her son, it's an FMC slice-of-live game or an MMC playing-the-field game or harem game. It often starts with the realisation that her son, who's been through puberty for years usually, has erections. Yes these mothers are nothing if not perceptive and quick on the uptake. Often she wonders if it's painful or he says it's painful and the idea she should get her hands dirty is suggested and, because she's a complete moron, she falls for it. This starts her reluctant progression from mother to handmaiden to, if it's an incest harem game, harem member. Maybe even best girl if she's
really lucky. Gotta respect her playing the long game like a pro though, priming the pump to get pumped by her son in his prime.
Though priming the pump often means his seed will flow into other places too. Did anyone ever bother to warn her about the NTR risk?
In rare cases it may be about a futa daughter, who's then often the MC, but overall the scenario's then still pretty similar to a mother giving her son a hand.
But if the father "educates" a daughter, you can bet he's usually the MC, and much less reluctant, though maybe he's somewhat aware that it's socially inappropriate, and a pretty eager pervert. If he's aware of the inappropriateness he may sell it off as just helping out one time, if not it's usually a plan to conquer her. The daughter, taking after her mother as a complete moron, often is totally clueless about masturbation. The first lesson triggers a powerful mental age regression in the daughter, who becomes needier and relies more and more on daddy. Soon he decides she's ready for the next step, or he's quickly convinced to show her what's next. By then daddy takes up her entire mental world, and she bends the knee and opens her legs for daddy's parental guidance.