So, in my none-of-you-even-know-the-source-material fandom, I fairly recently wrote two stories with sexually explicit scenes, my first of those in literally several decades. I'm old-fashioned enough that there was a main story, and then there were "adult" stories for two of the main characters, a remnant of the time when there were separate zines and websites for slash & het adult stories, in days of yore. (AKA, the 90s.)

But yeah, in both stories, the sex was very much connected to what was going on in the larger narrative -- in one case, a character reaching out to her partner in need of connection after a traumatic experience and in the other, casual sex helping someone with a broken heart beginning to move past it. And apparently I can only write sex scenes when there are Reasons. I don't think I could have written it had it been obligatory.