its hard to earn with adult sites since most visitors come to watch some vids ..relief themselves and leave, what you can try is some ppc (pay per click) on the side of each loading video and some cpm banners and to my experience niche sites sometimes tend to do better but really to earn more with adult sites you just need more traffic because most of the traffic quality is shit.
...If I'm in the middle of touching myself, I don't give two shits about affiliates.