Let's start off with a little breath play.

Duromast finally releases her throat letting her gasp for breath. Though clearly a bit more frightened of the large demon seated before her, she obediently stands still, waiting for his command. After rummaging though some trinkets on his desk the demon quickly finds what he was looking for, a small choker made of a fine black lace. He opens the silver clasp and places it gently around the girl's throat, it's a tight fit but the lace stretches comfortably around her neck. Cinnamon reaches up and touches the choker carefully. Thinking she had just been given a gift she says, "Thank you Master."

In truth it's a deceptive artifact, one he made himself many years ago. By itself it's harmless, beneficial even. When worn it simply keeps the wearer's blood oxygenated, eliminated the need to breathe. However, just removing the need to breathe doesn't remove that deeply instinctive desire to do so.

The demon nods and smiles. "Thank me properly for it," he says gesturing down towards his naked crotch. Smiling and nodding enthusiastically, Cinnamon kneels in front of the demon lord, pulling the head of his soft cock between her lips, kissing and suckling on the thick head while reaching up to gently stroke along the shaft with her fingertips. Duromast, as a demon who makes a habit of fucking humans, keeps his cock at a somewhat reasonable size, for a demon lord at least. For a demon lord though, a reasonable size means as large as most humans can take without killing them. In fact, when fully erect he's larger than most horses. Even fully soft as he his now his cock is longer and thicker than most men. Cinnamon though has been well trained, and with each gentle bob of her head pulls more of his soft cock into her mouth. The demon's cockhead, thick as a plum, pushes up against her throat which she squeezes by swallowing.