Proceed with feeding Rachel your essence while Kyle watches

Prompt: Proceed with feeding Rachel your essence while Kyle watches.

Turn 21:

You move to the bed where Rachel waits, her transformed body trembling with need. Her skin has taken on patterns like heat shimmer, reds and deeper crimsons pooling beneath the surface. The horns curving from her temples pulse visibly with each heartbeat.

"Please," she breathes, spreading herself wider. "I'm burning up. I need—"

You silence her by pressing two fingers against her lips. She understands immediately, opening her mouth to accept them, sucking with **** hunger. Your essence flows into her—not the thick fluid from before, but something more refined, distilled from shadow and ancient appetites.

Rachel's eyes roll back. Her body convulses, spine arching off the mattress as the transformation accelerates. The reddish patterns spread like spilled wine across her torso, her breasts, down her thighs. The horns push forward another two inches, thickening at the base where they emerge from her skull.

"Oh god," Kyle gasps from his position on the floor. His hand has moved to his cock without conscious decision, pulling it free from his pajama pants. Despite the raw soreness, despite having come five times already, his body responds to what it witnesses. "Rachel, what's happening to you?"

"Evolution," Rachel moans around your fingers, her voice deepening with new harmonics. "I'm becoming what I was always meant to be." She pulls your hand from her mouth and guides it between her legs. Your fingers slide into her heat, and she cries out—a sound that rattles the windows.

Kyle strokes himself faster, his eyes locked on his sister's transforming body. Tears stream down his face even as his hips thrust forward into his fist. "This is wrong," he whispers. "This is so fucking wrong." But he doesn't stop. Can't stop.

You withdraw your fingers from Rachel and bring them to your own sex, gathering the darker essence that pools there. When you bring your hand back to Rachel's mouth, she lunges for it, licking your fingers clean with a tongue that has grown slightly forked at the tip.

"More," she demands. "Give me more."

You position yourself over her face, and Rachel understands. She grips your thighs and pulls you down against her mouth with shocking strength. Her new tongue works inside you with inhuman dexterity, drinking directly from the source while her own body continues to shift and change.

The horns have grown to four inches now, curving back over her skull like a crown. Her eyes have shifted to a deep amber color that glows faintly in the morning light. Her fingernails have darkened to black and lengthened into sharp points that dig into your flesh as she feeds.

Kyle makes a choked sound. His hand moves frantically now, his thin stream of semen splattering across his sister's carpet. But his cock doesn't soften. Instead it pulses, ready again almost immediately.

"Watch," you tell him, grinding against Rachel's eager mouth. "Watch your sister become something greater than human. This is what she chose. This is what she wants."

"Yes," Rachel gasps between licks, her voice now carrying an unmistakable demonic resonance. "This is exactly what I want."