Lover’s Shadow is a direct sequel to The Lady Riding Atop and Demon Bride. However, it’s written so you can join here. If you do, then while Ashley is collecting clues to understand what is going on at Passion Mill, you’ll find yourself collecting clues about the culture. Don’t worry, you get at least as many clues as she does. If you’d prefer things spelled out more clearly, read the others first. Reading the rest of the series after Lovers Shadow is fun too.
Attitudes towards promiscuity and taboo sexuality like pee play are very different here. I hope you walk away realizing how much the intent of those involved affects what sexuality is. Perhaps you’ll even bring the power to decide your own intent into your own lover’s work.