Renderotica

In order to get a really solid answer on that, I'd try messaging BlackAdder directly and asking. They may or may not be willing to answer. 

I've been playing with this shit for 20 years, and to my somewhat trained eye, it doesn't really look like they/he/she is using anything other than either iRay in Daz or Firefly in Poser. I have read that custom morphs are used in order to get the body shapes and genital expansion to create the images, but that can be done in free programs like Blender, I think even Daz's Hexagon is free, or at least cheap. 

There may be some postwork going on in Photoshop or Lightroom, but what BlackAdder is making, while very good, is not unattainable by you. Lighting is key, and probably the most important aspect of an image. A well lit scene with a lot of flaws like intersections and texture problems will look better than an otherwise perfect scene with poor lighting. So, get your lighting right, then work on the rest. Check out the tutorials on YouTube for Studio, there's days worth of watching over there. Once you're comfortable with lighting, inspect your scene for flaws. Is there a fingertip protruding through a thigh? Buttcheek pushing too far into the bed? Hair intersecting with the shoulder? Do a lot of test renders, and look for things that distract you from the focal point. No render is ever perfect, but they can be made less flawed by paying attention to the details. Above all, have fun. This is a hobby. :)