This is a scenario that I've played around with a number of times (and probably will again in the future) about a princess being sent out into the wilderness to learn about sex the "natural way"... from nature. In this version, it's an accidental mishap that occurs during a coming-of-age ritual. Come to think of it, perhaps I should add more to this story. It's one of my more popular ones for some reason.
I attempted a deliberate approach to sexual suspense in this one. Hentai stories tend to build situations like a crescendo, becomeing more instense as they go. But in this one, I increased the sexual suspense in sort of a stair-step pattern. I would start off mild, then show something fairly erotic, back off slightly, show something even more intense, back off a little, etc... I selected and portrayed situations with an awareness of how exciting each one was. Generally making them more and more intense as the story progressed. But the stair-step pattern introduces a contrast between action moments and restful moments. (much the way movies do) I did the same thing with my old Zelda game. You can see some of my design notes for the suspense in the downloadable version of this story.