The first chapter of the Master Downstairs was just an idea that stuck in my head for a month or two. It wasn't a fully formed story, it was just that tension of "a naked woman in the living room and the eerily calm way she told me my wife was downstairs with the Master."
What I've learned since then is that writing these types of stories is not "exciting" in the way reading one tends to be. It's your story, the only surprise is what you craft for the readers. You tend to be more worried about continuity or story gaps, perhaps with typos than with the actual sex scenes.
What is exciting is getting feedback, of all types. I now make a practice of giving feedback to almost every story I read all the way through. Sometimes it's just pointing out a few things I'd appreciate being told about. Other times, it's to say I really liked a character. It doesn't take much, but I like doing it. Maybe one of them like me, would not have written more than the first chapter unless people wrote in and said they liked it.
There are 2-3 more Interludes chapters and another full story shaping up right now. I'll probably start posting in August.
Enjoy your Northern Hemisphere summer!