I had the interesting experience of writing of writing a story that works both with and without the erotic element. I know they say that that sex should only be included if it's essential, but there's a line between not-strictly-necessary and gratuitous, and I somehow managed to stay on this side of it. In this case, I kept coming upon moments where I wanted to spin up the tension dial and have meaningful — okay, hot and heavy — moments, but I held myself back.
I actually like the way it turned out. There's nothing definitive you can point to and say, "These characters have something for each other." But it's implied all over the place, and you can easily imagine how the relationship forms and gets more serious past the official end of the story.
But naturally I'll write in the erotic bits before I post it.