From a content point, I like it. If this kind of content was in one of the many the big brother reboots, and spin offs I might actually engage with it. I'd like to see some vaginal sex and some knotting but you're off to a good start. A catch-all term to help you make any creative work better is "verisimilitude". It applies to everything but abstract and absurdist art.
Your pose variety in this set is good, but emotive posing and visual storytelling can help make it better. For example Ann's missionary with the pig could be more impactful if she was cuddling/hugging the pig tightly it would hit differently feeling almost romantic. Similarly, if she's curled into him with her upper body you can better show one of her breasts and get a second perspective for the pose showing the animal from behind cumming inside her vagina while she cuddles it and looks at the viewer.
From a technical perspective... well a mostly mud perspective since the images look pretty good overall.
- Less is more, the "dirty" texture on the characters felt a bit excessive in places and too clean in others. With mud that wet and thick it felt incongruent.
-You can reduce the depth because it doesn't need to be that deep. Also, depending on how watery the mud is they'd sink differently. More surface area will distribute the weight more evenly so they wouldn't sink as much or there would be a difference in how deep each body part.
- Visually add some gradation (lighter colored mud) to show partially dry sections of mud at the edges to make it flow better. What you did isn't bad but darker valleys and pale peaks to reflect sun drying and water flowing. The Ann, Lisa and Pig image gets this best.
Overall, good job. I'm looking forward to seeing more.
