As he commanded her, the man buried himself to the hilt in Christie's wet tunnel. Her silken skirt bunched up between them while he ground into her, rubbing her most sensitive spot rhythmically. Christie gasped sharply as he momentarily tightened his hand around her neck. Her mind was a chaotic wreck as the still new sensations of her overstimulated body flooded in—that resistance still alive somewhere—and with a last desperate effort she moaned out a futile "Nooooo... "
But it was too late. Something had snapped. Her arms wrapped around the man's strong back and dug in. Her hips raised and lowered on their own while her pussy tightened and relaxed rhythmically. She bucked and twisted with increasing desperation as her instincts took over. She needed to cum. She needed to obey. It felt so fucking GOOD. As her clit slid along the man's throbbing cock she came. Her whole body tensed at once as she screamed out, "Oh God yes! Yes! Yes! Ooooh!".
The collar clicked again and the man smiled slightly. His hand slid off her collar and around the back of her skirt before forcefully grabbing her thick ass and pulling her onto his trembling cock.
"That's a good girl. Time to unload..." he grunted.
Her mind was still fuzzy as he continued rutting her with new urgency. As she faded back in from the highs of her orgasm she was immediately overcome with instinctual glee at the thought of accepting her master's load. Her hands shifted down to the man's ass as she pulled him in, willingly giving herself for his use.
"Ooooooh... YESS... master..." she warbled, "c.. cum in meee.."
With that they primally pulled each other closer, and the man released himself into her. The collar tightened slightly, and Christie came again. She moaned "yes... yessss" over and over as each red hot load shot into her. She felt heat flow from his cock and into her with each pump, filling her body with warmth. As the man's final spasms slowed, Christie's hungry pussy clamped tightly, eliciting a final massive load from the cock buried inside her. She smiled vacantly as the man slowly slid out of her and rose to admire his handiwork.
"There. Just relax while the collar does its job. When you came, it finished making you a submissive nympho. Now that I've cum inside you, it will mold your body to my whim." Slowly, he started to rub his still swollen cock. "It's always fun to watch the changes."
Christie could barely make sense of his last statement as she started to get back up. She kept trying to think, but the sensations that had just washed over her left her helpless. She came... twice... and it felt so good... She sat on the end of the bed confused for a moment before she could feel her attention shift towards a new warmth spreading through her body. Her breaths suddenly became sharper as she began to panic. A tingling sensation spread across her body and she looked up at the man with frightened doe eyes.
"Master!"
With sudden urgency she lunged forward at him as her legs began to spasm. Despite being weak from being fucked twice, her muscles flexed forcefully and began to expand. She leaned into the man for support as her calves tightened and swelled slightly. Her thighs, jiggling from her sudden movements, slowly started to tighten up as well, filling out with thick muscle. She gripped the man tightly as the sensation kept flowing up her body, into her hips and ass. Her bounteous rear tightened into a round and shapely ass while she subconsciously swayed her hips back and forth, popping a bit each time. They grew wider with each pop, forcing her to spread her stance bit by bit. By the time it was over her lower body was nothing but well defined curves.
Now that she realized what was happening, she gazed up at her master in joy. "Thank you master! Make me all yours, make me whatever you want! I need more!"