Almost all of the smut scenes are from my own fantasies. I have a habit of creating all kinds of scenes while you know... having fun with myself. :D And I just adjust them to fit my characters, or just draw some kind of inspiration from them. But some of them, I just figure out along the way while writing, when the characters develop, it's easy to think about all the kinky stuff they would do.
There are only a couple of scenes that were inspired by one performance in one of the kink/bdsm parties I have attended. There was a performance with shibari bondage, and I thought it was hot as fuck. And my newest novel is basically all about bondage, so that fitted perfectly in that.