This is a tricky question, I'm not sure how to approach it.
First, the context. You're making a porn game. I don't know what kind of game you're going for or the kinks you're going to add, but the staple of porn is that it isn't realistic. Porn is this alternate dimension where virgins don't feel pain the first time they have sex, where women have three orgasms while the dude just lays back, and if you rape a girl long enough, she'll end up enjoying it. Those things might sound sexy depending on the person you are, but it doesn't make a lot of sense if you think about it. But it's not supposed to. It would be boring otherwise.
So, in a way, "a meme" is right, as far as the porn action goes. Think about what you want to do, and do it "by the books". Realism is not the focus here.
Although it is possible to make an unrealistic porn scene more than that. The games I like the more are the ones where characters, both males and females, are developped enough, to the point where you can relate or atleast understand their progression and how one ends up fucking the other. If you want a game that completely fails at achieving that, just take Big Brother, it's hilarious. If you want a game that tries to do it but also fails, look at DatingMyDaughter.
In Big Brother, it's easy. The characters have no character. They might aswell be called "sex template 1" and so on.
In Dating My Daughter, the daughter seems to have some character, but she's completely unrelatable. No idea what sex is, 100% oblivious to the fact that she's hot (if you think a 14 year old is hot), laughably stupid. Her brown hair friend is pretty much on the same level, but on the opposite side of the spectrum. Her motivation in life is "be horny" and "be available for MC". She might aswell be lost in time whenever she's not around.
To me, that's what sells a character. Being able to picture them outside of a scene they're in and imagine what their day to day life would be like. It's much more satisfying to see characters interact with each other and their relationship evolve if you can understand why things are progressing this way, rather than seeing a sex session out of nowhere because "that's what happens in a porn game".
If you neglect every aspect of your character but her sex drive, you're just making a target for Sarkeesian. Think of sex as just another aspect of life, and not their sole motivation in life. Needless to say, if their sole motivation in life is the MC, it's even worse.
From that, you can go any direction you want, there isn't a template for making women or anything. The best way to go is to clearly define your character (shy, provocative, joyful, nervous, energetic, etc) and make sure their actions don't contradict these traits.
Firstly, when you're alone how do you refer to your genitals. In your thoughts is it "my vagina" do you think "pussy". I had a friend read my script for my character's masturbation scene and she didn't feel like the word pussy fit. When I pressed her though she couldn't come up with how she feels she would have referred to it.
It really depends from a person to another. Women are not different from men, there isn't a stereotype that will apply to all of them. In relation to what I was saying, if your character is hot and knows it, she could say "pussy" because she knows it would arouse the person she's trying to fuck. Makes me think of Ygritte in Game of Thrones (maybe not the best reference, but a lot of people will get it), she acts a certain way towards Jon because she understands how he is.
As far as argot goes, I don't find it very sexy, but it's better in english. My main language is french, and the literal translation for those is just plain unappealing. Like, yuck.
Second, what are some ways you've been proactive yourselves in real life. No need to be graphic, I'm not looking to appropriate your experiences, simply looking for some inspiration as to how to write. Too often I find female characters in these stories either don't act, or they are crazed sex addicts who worship the dick. I'd like some examples to work with for an appropriate level of how a normal girl thinks to act.
Well, for one, the dick worshipping isn't real. It makes me cringe every time I see it in games/hentai, like "I've fallen in love with the D". Urgh.
So again, that will depend on the behaviour of the character. People in general also like to pretend they don't just intend to have sex with each other, both people act as if "it's not about that, we're just having a conversation because we appreciate what we have in common and what we don't have in common". Which is true, too, but people don't often admit their real intention is to get laid. Everyone wants to keep a classier image than that.
Lastly, are there any common things that always make you cringe when reading female characters?
Well, I've already tackled that here and there, but it wouldn't hurt to reiterate. Of course, these are just things I don't like, it won't be true for everyone.
1. No MC worshipping. MC is just a guy, and there are billions of those things.
2. No dick worshipping. Just... get over it.
3. No sex object. If you want your female to be a character, she has to act like a female, and not just something to be used in a later sex scene. It's also boring to play a game that predictable.
I want to write a character who can still maintain her self respect while also being a slut. I want to write a woman who accepts being a slut, so that every time she gets accused of it she owns it, but who isn't a weak little bitch.
Tricky again. I don't think any woman would like being called a slut by just anyone, unless they have that particular kink. Things that are arousing during sex often aren't outside of sex. And many things are arousing because of the person you're doing said things with.
To sum up, the way I would go about it is just picture the character through her life, and not just at a particular moment (when she meets the love interest). Every decision matches their character and their life experience. Not every decision revolves around MC. I know it isn't very specific, but that's because you don't have to be reductive when it comes to a female character. Colourful females can exist and be relatable and fun to play with. But it needs to have some sort of logic in there.
What you're saying is the equivalent of making a porn movie where you zoom in on the dude's face when he's about to shoot his load. I'm sure women love that
Do they really?