Hi, about this sex scene, I was curious about what would you think as a reader or as a fellow writer about th (...)

#1

First, I'd like to say that I'm a coward, so I'm posting from an alt account to avoid my story being 0.5 bombed.
So basically, the theme of my novel is how immortality (to be exact, eutheurealism; my MC are dragons) influences the main cast. 
The premise of my novel is that the main character was, in his past life, a dragon, and so was the fmc. Back then, despite having lived for millenials, they remained, how to put it, "Childish" were the only two dragons in the world they were in. 
And dragons need some sort of mentor to grow.
At the end of the story, the two of them end up killing each other (accidentally, but they still pretty much kill each other).
Both reincarnated (no memory) into humans but in two different timeframes. One was born in the year 125, while the other was born in the year 2000 or so. The first dragon reincarnated is a female (she's the fmc after all). She reincarnated as the sick daughter of a powerful mage. To save her, the mage freezes her for 1900 years (yeah plot convinience, I know). She is discovered by our MC (who on his side was progressivelly getting back despite his reincarnation to his dragon state) and things evolve between the two.
They fell in love, and both eventually abandoned their human state to return to their former dragon form (basically, it was impossible to trap a dragon soul inside a human body.)
Basically, the lore of my novel is strict about the stage of a dragon's life:
First, you have the enfancy. They would have the mindset of a 10-year-old (if they took human form, they would look like a ten-year-old child).
The next stage is the teen years (this is the whole point of the reincarnation; a dragon can't grow without someone as some sort of mentor, or senpai, or whatever. As a dragon, they had no one like that, but as a human, they did). Basically, they would be the equivalent of a 15-year old.
Now that you pretty much get the whole mess,
Here comes the problem: a sex scene.
There is a goddamn sex scene. My MC and my FFMC are literally 15 years old.
I was curious as a reader how you would feel about it. (One of my first novels is Mushoku Tensei, so you would understand how my subjective opinion on the matter would be quite (if you've read Mushoku) you know.
Is the sex scene really needed?
-Yes
Despite what you've read, the plot of this novel is as much plot-driven as it is character-driven, and that sex scene appears near the end of my novel. My novel ends with the humans (secondary characters) that help them grow as a dragon achieves their goal.
For the Mc, it is her sister: She is the MC's elder sister by four years; she was 19 when she accomplished her lifetime goal.
For the Fmc, it is the mc: When the mc reached adolescence, so did she, because she found the senpai her inner dragon required in him.
So basically, the novel ends with both of them still being 15 years old as humans, so the sex scene has to occur somewhere during that time frame, or else it will never happen (and that will fuck up an entire mini-arc, lol).
Why not change these dragon rules?
It's too late. The whole world building (people of my world are revering dragons as gods), the whole foreshadowing is set. I can't go back anymore. 
So here again, I ask, how would you, as a reader, react to this?
When I first read about the scene in Mushoku, I wasn't weirded by it since, back then, I was around 16 or 15, when I first read about it, so it felt pretty much normal to me, but now that I'm an adult, writing a sex scene involving, well, let's call it what it is, a minor feels just weird.

Don't get me wrong, I'm not asking whether or not I should write this (I will, I'm halfway done, I can't back up anymore), I just curious how you would react to it (to ready myself for the backlash) DrakanFascinating .

Edit: This scene is not meant to be graphic, Titanic level one (You know just enough for the reader to know they did it).

Re: Hi, about this sex scene, I was curious about what would you think as a reader or as a fellow writer about(...)

#2
If it's a makeout fade to black, it's no harm no foul. If it's graphic, you could get some shit for it.
This is not new, graphic sex between minors has been avoided by writers for a long time.

Minors having sex is not the problem, it's minors having graphic sex with a presumably adult audience that is the problem.
I am not saying you cannot get away with it. Hell, Piers Anthony got away with describing graphic sex between a 40 year old man and a 6 year old girl. But do you really want to?

Re: Hi, about this sex scene, I was curious about what would you think as a reader or as a fellow writer about(...)

#3
Uhhh, I believe no art should be censored, so ig go for it??

I mean if you're so afraid of the backlash, then don't. 

If you're gonna do/show something controversial, you SHOW it. No half-assed safe approach. If they have sex and if it's absolutely needed, then SHOW it. You're all in or all out. 

So basically, face the music and show it or scrap it. No in-betweens.

Re: Hi, about this sex scene, I was curious about what would you think as a reader or as a fellow writer about(...)

#4
May want to first check with the mods because I remember age of consent was needed and was set at 18 thus you can only have fade to black and only if the admins allow it. And me in particular would skip it. Not because of the 15 thing, as a 17 year old I don't care, I just don't like reading sex scenes in plot books. If I want them I go read erotica.

Hope that helps!!!

Re: Hi, about this sex scene, I was curious about what would you think as a reader or as a fellow writer about(...)

#6
Oh my.
That's a complicated question... I live a good, romantic love-scene if it's done well. 
Like the poster above said, I'd recommend leaning into it if it's necessary. What calls for necessary, however, that's a bit hard to say... There may be backlash, so I'd say that really depends on how ready you are to sit there in the trench while the 0.5s and 5s battle it out above you.
Then again: Stephen King's "it" featured an orgy between all the underaged MCs if I' m not mistaken and that's gotten like 4 movies. 

Re: Hi, about this sex scene, I was curious about what would you think as a reader or as a fellow writer about(...)

#8
There would certainly be backslashes. Mushoku Tensei got a fair among as I recall. 

I won’t talked about the fact if they would the sex scene or not because as say by Random Cat people would just skip it sometimes. On the subject of the problem of age, I would say it depends on what is important for your reader. 

Sexual maturity: around 13 years old, below that is a big no go. 

Mental maturity: hard to determine since it would depend on the intellects and experiences of characters.  (For me I consider that in Mushoku Tensei, Eris had reached this stage due to all the shit she had been through.) However, it is necessary to give consent. 

Legal Maturity: In our world it goes from 16 to 21 currently, but it was near 12 and 13 in some period of our history. In Mushoku tensei it was 15, so in this sense Rudeus was still considered a child, and Eris would be the pedo. However everyone dismissed this since he had the mind of a 40 years old man. 

Physical maturity: Our bodies stop to change completely around 14 to 25 years old, but this is highly variable, so it is often dismissed. 

As a reader, I would say that your case check, sexual, Mentaln and Legal (in your world) maturity so I will give you a pass. However, other people can be less open-minded on this type of subject.