>>2602369I guess I'll give an idea of how I would approach it.
>>2595288In this scenario here, I wouldn't just do that hentai thing where the opening line is the MC just describing the gimmick like "today is foot fetish day at school." I'd start with asking myself if a foot fetish club were to hypothetically exist what would happen? Obviously the answer is "nothing good." It would be an epic shit show in real life. But thinking through that helps because at some point in the chain of logic you can find a branching point where you make one subtle change and it veers off course straight into the fiction you're trying to tell. People would realistically be grossed out and appalled. Well, let them be. Let them go through all the real stuff but instead of letting that stop the club from existing, let it happen anyway in spite of it. Now you have your story but it's anchored in honesty. Let the characters acknowledge the weirdness in their own voice and come to whatever conclusions they plausibly would. Don't force your characters to blindly go along with the story.
A lot of hentai makes the mistake of just having the MC announce what the concept is. "Today is nude day at work so everyone arrived naked." "Oh, Takeshi, good to see you. I see your dick is out...as it should be...since this is nude day at work."
Something like nude day isn't a thing that happens so you have to be honest about that up front. You either have to establish that it is happening anyway despite being inherently problematic or establish why something so problematic has become a normal thing in the first place. Let the dialogue convey the sentiments at play.