Not much feedback as of recent? Oh well.
I've gone thround some of your pictures and found some mistakes that should be adressed.
Starting with your Study from the 18th, the woman had a broken right shoulder, aswell as a very concaved left elbow. When someone is sleeping, the person is very relaxed, so the pose should reflext that. About the right arm: Given the "kinda-sort-of" perspective of the sketch, it would be hidden behind the torso and the head.
If it was in a more overhead perspective, you would have to create a clearer connection between the back and the shoulder.
Also, keep in mind that humans are made out of flesh, not from plastic. Muscles move not only if we relax or stress them, but also when they come in contact with other objects. Keeping that in mind, the thigh would flatten slightly over the tibia.
The Pic withthe tied woman and the poacher Naruto looking fella (?!) suffers from many anatomical errors. Legs and arms being too short, the head of the poacher being too thin, his ear being completely flat, aswell as the womans odd shoulder muscles and baloon breasts.
It shows that you have little understanding of basic human proportions and anatomy, which, for a pornographer, is anything but good. I did the redline to illustrate how one could fix said problems. I included a share of sketches on the right side of it to give you a quick guide on how to draw breasts. You see, breasts are subjected to gravity, too. Thus, they are pulled down.
The final one, THIS ONE, has different problems. Although some things got better, the way the woman poses here would break her spine. Also, the man looks like he is about to fall over given the angle. The also seems to be little regard for other muscle groups like the serratus anterior, the external oblique or even the biceps.
The Pose of him in general is not alot better. Granted, we can see very little of it (most of it is hidden behind the table), but it still looks very stiff (Falloing over stiff as a board). The position of his left arm gives the idea he is grasping between her legs, btw. I know its erotica, but it seems rather nonsensical given the scenario here.
Below I sketched how the position of the individual body parts could be, aswell as a sideview of the woman resting on the table in her fixed pose.
You need to work on your proportional and anatomical understanding and get an idea of how to picture a three-dimentional object in a two-dimentional medium. Things like correct optic shortening, being able to draw different body parts in different perspectives etc.
You should also practice how the human body moves and expresses itself as a whole. Make gesture sketches, focusing not on a detailed depiction of a human, but more on an expressive, yet marginally proportionate correct one.
Good websites to do these things are QuickPoses and Pixelovety, but you can also go outside and draw real people in public. In fact, this is one of the best things you can do, since the people are not going to slow down and pose for you. You better be quick with your pencil.
If you intend to draw more erotica (and I believe you do), I recomment trying to resort to less porn stereotypes. There are some things, some poses, some scenarios that have been done ad infinitum that just do not stand out anymore. I'm not suggesting that you should go full crazy on your works, but you may want to create some themes and characters in your work that make is stand out. Perhaps affectionate intercourse? More playfull one? Maybe BDSM? Some unique angles? Having own characters with own their own personality and preferences have it together (you can tell alot about a character just by the way they look, move or speak. No need for long introductions or Bios )? Something that makes your work stand out from the crowd.