>>29242
Likewise.
The one idea in particular I've been cultivating the last few years involves the PC traveling to a Pacific archipelago, building a home, and discovering it's already somewhat inhabited.
There's a few (monster)girls there, the spirits of virgins sacrificed to the volcano god (who, punished by higher gods, is now also mortal).
The volcano god's remaining power can be eroded by making these virgins into non-virgins.
The PC will be there for a while, ultimately for several years, possibly starting a family with one of the girls.
OP, it depends what gets you off, or your target demo. Dicks get triggered by whatever. I hate vapid women, coincidentally a woman stuck on an island has little choice but to acknowledge reality around her. I have a pregnancy fetish, hence -> PC-can-start-a-family.
Try just writing out rough lewd scenes and flesh them out later. Focus on building a general narrative, and that way you don't waste your time writing things that you later decide suck.
Did you have any specific thoughts about what you want to do in your story? Have you played that halfchan collab VN from a few years back?