In a world dominated by demons, humanity was treated as playthings, pets, and most importantly, source of sustenance for the demons. Generations of humans were raised and kept in ranches so to provide a stable supply of "produce" for demon consumption. Our RP would take place in a pretty "nice" ranch where all the human cattle were well fed, well pampered, and well fucked. Every day they eat, sleep, play, exercise, and of course get milked for their cum, which would be bottled, transported and sold across the world. The best part is, often they'd even have the privilege to be milked directly by their demonic masters instead of the milking machines.
Character A would be a perfect specimen who was born and raised in the ranch, while character B would be a "wild" human who got captured by the demons then sent here. A being the "model cattle" was tasked by his demonic masters to look after B to help adjust to his new home while character B obviously didn't want any part of this, but the comfort and pleasure of living at the ranch would constantly challenge his resolve, not to mention the fact that B pretty much fell in love with A on first sight. Would A convince B to stay at the ranch and live the rest of their lives in leisure? Or would B convince A to venture out into a horrifying yet free world?