With enthusiasm

"Yes! If its your pussy, Mary, I happily accept!"

Mary grinned a fang-filled grin. "Good, off the bed for a second."

Tanya obeyed as Mary took her place. Mary was concerned her larger form would crush Tanya, so instead opted to lie on the bed first. It was reinforced to hold the Succubus Princess' increased weight. Clearly her mother was prepared for just such an issue.

"Now, Tanya," Mary began, spreading her legs, with one long, statuesque limb stretched into the air. "I wish to feel your sex upon mine. Scissor your princess!"

Tanya eagerly climbed on the bed, positioning her own legs. For a moment Tanya felt a little overwhelmed at the far greater size Mary possessed now. Mary's cocktail moved up and caressed Tanya's cheek affectionately.

"I will love it," Mary assured her. "Besides, it won't be an issue for you for long."

"Okay," Tanya said, moving to press her pussy against Mary's. Tanya felt an instant electric shock of pleasure when their most intimate folds touched each other,

"Yes, that's it," Mary encouraged. "Harder! Hard as you can!"

Tanya obeyed, continuing to rub herself against Mary's sex with increased speed. Meanwhile Mary's cocktail had slithered up once more and began to try and worm its way between Tanya's ample asscheeks.

"Do it. Accept me into you," Mary instructed.

Tanya leaned to her side, bringing a hand down to grab one of her buttcheeks and pull it up. The tail quickly made its way inside

"Fuck!" Tanya gasped. "That..shit..it..it feels good!"

Mary smiled. "It's already happening, Tanya. Your body's transforming. One of the perks of being a succubus is that, like your pussy, a succubus' ass has pleasure nerves inside it." Mary's tail started thrusting back and forth inside Tanya's ass. The cries of pleasure Tanya gave only proved Mary's points. "Still, there is some pain leftover. I mean it wouldn't be anal sex without a little pain to sharpen the sensation." As they continued to rub themselves against each, more Mary's cum was starting to make itself way inside Tanya, converting her body's insides to handle the upcoming transformation. "And the final touch." The cocktail suddenly explodes into Tanya's ass, filling her with demonic essence.

Tanya started taking a series of rapid breaths. "Fuck! I'm..cumming! Over and..over!"

Mary watched with enraptured anticipation. She watched as Tanya's body grew in stature until she was nearly as tall as Mary. Her already respectable breasts enlarging to match Mary's impressive bust. Mary watched Tanya's hips expand and her waist shrink. She felt a pang of annoyance that she couldn't see Tanya's new ass from this angle, but reasoned she'd have all eternity to see it whenever she pleased. Her black skin shifted into an alluring onyx shade, almost metallic in sheen. Four individual horns grew separately from the top of Tanya's head, two larger ones near her ears, and a smaller pair between them. A ruby formed between Tanya's breasts while a series of smaller ones appeared along her forehead. Less prominent, but no less beautiful jewelry formed along her wrists, neck, and ankles. Several diamond-like piercings formed on her ear lobes, and another on her belly button.

"My, my," Mary said with a big grin. "You're lovelier than I expected. And I already had high expectations."

Tanya stretched out her new muscles, her new breasts pushed outwards, making Mary's mouth water.

"I feel great! Like a goddess that would make men drop to their knees!" She admired her new muscles and curves.

"Would you like to take your new body for a test drive, my handmaiden?"

"Oh yes."