One guy asked me a question so I answer here.
About the motivation of being seduced or fall of heroine:
I mean, it is OK to describe the fall of heroine using conventional usual cliche, such as BBC or ugly old guy with big dick or etc. I'm not saying let's exclude them all. But those "conventional" reasons should NOT be the ONLY reason to being seduced or fallen. There should be other good and reasonable motivations for heroine to decide reluctantly cheat on their BF or hubby. It is really really unlikely that any good and royal girlfriend or wife betrays their partner just because of one single sex with BBC and suddenly become slut/slave of pleasure. That is totally out of common sense at all.
There should be additional (one or two) very important and good motivation, about why heroine resist again and again but submits in the end. There should be a reasonable description about heroine's mind, explaining how she reluctantly decide to cheat on their important ones. And this reasons should be realistic, not absurdly naive or not too stupid.
Also, if the resistance and reluctance from heroine are described nicely, then that story will be much better. Stronger the resistance, more the pleasure from "conquest" during the NTR/NTL description. Plus, element of reluctance makes story much realistic. This make story/game long, but I guess such build up is very necessary for convincing storyline + fapping element. But authors need to careful not to make their story too long.
I think "Fallen after 1 sex" does not make sense, but if the story become too long, then maybe it would be better to finish the story with "Fallen after 1 sex" cliche, and continue from next part. For example, try to describe the "process of seduction" during part 1, and end the story after heroine is seduced and have a relationship with bad guy. Then, from part 2, the center of story now moves to 'pleasure from breaking taboo or continuing forbidden relation' rather than seduction itself, because the seduction is finished in part 1. To me, I think the process of seduction should be gradual and slow, but this depends on characters and environment.
Again, stereotype reasons or motivations like, 'bad guy is too good at sex' or BBC or BC or 'bad guy's sex/foreplay skill is too good' 'very charismatic/persuasive bad guy'... are OK to use. At the same time, weaknesses of heroine, like 'she is a little bit more naive then others' or 'she is so selfless and kind to others, that she feels hard to refuse when others asked a favor'... are also OK to exploit. But those should be well blended with other reasons and motivations, not being the only one factor of seduction.
There are many additional motivations to make the story more convincing. Blackmail, revenge of bad guy, too high pride/self-esteem of heroine, heroine feels guilty, or purely mistake, heroine is mentally tired or exhausted because of stress or work or her duty, heroine has a family issue or her husband is cheating, she is not satisfied or unhappy with husband (I know those are also cliche but it happens sometimes)...... But one thing should be clearly reasonable, about why heroine reluctantly continue the forbidden relationship, instead of calling police, husband, friend, or etc.
You could try unique background story or character setting too, like a bit of science fiction or feminism or etc. Using fantasy of science fiction make it bit more easy, because the story doesn't need to regulated by real-world laws and customs, yet still you can make it very realistic or very likely-to-happen story. If you have some good imagination then you could try good NTR one. I think superheroine story is actually very good to exploit. She looks very strong and powerful, and she really is. But she feels very lonely, or she is getting tired of being superhuman because of bad media or fake news, or etc... After all, she is also human and she is vulnerable to mental stress, although she is superhuman. Those can be a good weakness for bad guys to try something to her. Story can flows to full corruption, or she returns to justice but she already get impregnated, or etc... So many interesting possibilities. Vampire hunter or Demon hunter stories would be the similar. Those are already too famous cliche in so many Japanese games, but the strength of NTR/NTL feeling, the feeling of heroine's reluctant betrayal and the pleasure from secret forbidden sex, can be greatly increased. Of course, real-world background NTR stories are good too.
