Derrick looked between the two asses in her hands before deciding to upgrade her toy with both. Her own ass was already quite big, and while she wouldn't mind having it a bit bigger, Kyle's booty was in much more dire need, especially since she would be using it a lot.
"Turn around slut", She commanded her bitch.
He spun around, facing his ass towards her and tilting his head to look back at her. He knew that something fun was coming and tried to push his butt out so it might look bigger, smiling shyly as he did so.
Derrick licked her plump lips hungrily, eager to get started. When she took the women's asses, she also took off a good portion of their hips. An ass without hips was nothing, as were hips without ass. Derrick decided to start with the smaller booty first, wanting to finish with the larger one, to end with a bang so to speak. Her lust overtaking her, she shoved the stolen bottoms into her slut's, making his ripple and bounce as they were added to him. His lower body was now much more pleasant to look at. It was wide and jutted out in the most attractive ways.
"Oh mistress my butt looks so nice and plump! Thank you!", he said excitedly as he wiggled his hips. Derrick stared at him longingly, thinking of what it might be like to put him in heels, to have him walk with his hips swaying in a wonderful manner. She caught herself drooling at the thought, saliva dripped from her juicy lips, dribbling over her titanic titties.
After clearing her head of that, she thought about how she wanted to further upgrade her boy toy. The first one was much too quick and she was hardly able to enjoy it. She wanted to be able to savour it this time. She gave the other woman's detached underside a squeeze, and then began to push it into her slut, slowly this time. Kyle moaned softly as his ass grew in size, his cheeks developing into soft pillows with his apps pushing out into sizable love handles. He could feel mistress squeezing his growing behind and loved how it felt. He then felt mistress take her hands off of him and was disappointed, thinking that it was already over.
"Aaaa!~ M- mistress!", he cried out as he was spanked, a stream of cum shooting out of his cock. The last of the upgrade had been pushed in by the force, and his ass jiggled wonderfully from it. His hips were now nearly as wide as his torso while his ass cheeks had grown to the size of watermelons.
"Ohh yes~ this is much better", Derrick said lustfully as she played with her toy's tush, "but now I almost feel like your legs need an improvement too"
Kyle bit his lip, the thought of what his goddess said made pre-cum drip from the tip of his cock. His ridges glistened with the clear liquid as he was shaken around by her ministrations.