Melany was becoming delirious, her mind totally overwhelmed by the pleasure and her body acting on its own. Gasping, panting and moaning, she could only ask for more, she was in a sensual bliss and wanted it to last forever. Jen was having a great fun and pleasure too but discovered that somehow she was still able to think clearly if she was thinking about the best way to give pleasure to somebody. If she tried to think about something else, she soon loosed it and could only go back to the pleasure.
"Mel wants more", she thought, "all right, let's give her more and even beyond…"
First she altered Mel's body, allowing her to live without breathing, eating, drinking or sleeping. She protected her sister's mind and so gave her the ability to feel enormous amounts of pleasure for long periods of time without passing out or have her mind blanked out. Then Jen began to expand slowly inside Mel making herself flow in her while expanding her sister's vagina. As she soon needed place, she made internal organs disappear inside Mel and filled her more and more. As she had changed and filled her belly (but it was not visible from outside) in a way that made Mel's belly being only a layer of skin and vaginal walls around the huge dildo that Jen was inside her, Mel rubbed it slowly, letting out a very deep growl of pleasure just before she yelled: "Yes! Yes! Turn me into an insatiable living pussy! I just want to be a hungry pussy!" Jen was too happy to please her sister and achieve her phantasm, she continued to expand inside her, pushing her vagina up into her torso making organs disappear in the way.
Once she had turned Mel's torso into a pussy, she made the same to her limbs and arms but let her head untouched. Soon her sister was unable to move as she now was a giant pussy moulded around a living black dildo which had the shape of her former body. Jen savoured the situation for a while as Mel felling orgasms one after another. Jen sent tendrils in the head of her sister, reaching her brain which allowed her to gain control over Mel's mouth and eyes. Then Jen looked down and moved her right "arm", she was satisfied to see the latex covered right arm of her sister move. Jen could move anyway she wanted as Kyle said but this was far more exciting. She stood up and went to her room where she looked at themselves in the mirror (after all, she was "wearing" Mel, somehow). She smiled and resorbed herself inside her sister to see her bare skin, as she did ans slid over her sensitive skin she felt Mel throb and spasm around and saw that it was hardly visible. She grinned and said: “ok, let's change all this so we can pay a visit to Kyle and thank him for this all new world of pleasure he gave us.”...
(Feel free to continue any branch of this story!)