Karyn's secret wish

Karyn would never tell anyone but she had a secret wish, one she'd imagined but never had told anyone about. She'd read stories online of things like it, where she'd gotten the idea from, though she'd never tell Jon. Now that she had snuck into his room at night and gotten the stone however she could make that secret wish a reality, the temptation was too much for her to bear so she began to say it just outside of Jon's room.
"I wish that Jon would want to have sex and crawl inside of me, and that when he did so my body would change to fit him much as a large snake when eating its prey. While Jon is inside of me I will have full control over what he will be reborn as living or inanimate. I will be able to take him back into my body at any time simply by saying the word secret while touching him." Karyn said, breathing heavily after the long winded wish. Sneaking back into his room she replaced the stone where it had been hidden and snuck back out of his house and back to her own, knowing that Jon would likely not be far behind.
Walking into her house she went up to her room and began to undress, slipping into her nightgown and crawling into her bed when suddenly Jon appeared in her room out of nowhere.
"What are you doing here?" She asked, sitting up in her bed, hiding a smile and trying to play along.
"I can't stand it anymore Karyn, I've loved you for a long time now I've just never been able to admit it. I know with this stone I could make you love me but I don't want that." Jon said, "please Karyn, just tonight."
"Less talk, more action," Karyn said beginning to get excited as she stood up, taking Jon's shirt off with a smile as he began to remove her nightgown. As the two began to kiss and undress each other they dropped back down onto the bed giggling as they felt each other. Karyn could feel Jon began to work her lower half, slowly stretching it as he began to take his fingers deeper into her. Oddly enough it didn't hurt as he continued to stretch her clit slowly but instead pleasure as first he put one hand, then the second, into her. As she laid there he slowly began to move his head downward, kissing her playfully as he went along, moving lower until finally he came to her clit, sticking his head into her as a new sensation began to move through her. She could feel Jon beginning to move inside of her, deeper and deeper in as more of him began to go into her, causing her to moan in pleasure as he continued. As she watched her stomach began to enlarge, as if she was rapidly going through pregnancy however she could also begin to feel another sensation. As Jon continued to enter into her she began to feel almost as if her legs were moving closer together, and beginning to widen. She could feel as if Jon were stretching the lower half the skin between her legs, merging her two legs together in the process. She could feel the bones melting and almost seeming to be moved around by Jon as he continued his way into her and yet even though it should have felt painful it felt as one of the most pleasurable thing she'd ever felt. As Jon finished making his way into her she could feel her legs lengthening, but instead of two legs it now felt as more of a tail. As it continued to lengthen she could feel her skin begin to fragment and harden, becomming more scale-like as she recalled herself with the wish and knew what was happening, her lower half was becoming more like a snake, she was becoming a Lamaie as she'd read about; half human, half snake. As she felt the changes begin to stop she put a hand on the bulge in her stomach, feeling Jon inside, curled up as a child would be inside of a mother. She could feel her body slowly working on Jon, almost as if it were digesting the excess. Smiling as she began to move her tail she began thinking about what to turn Jon into while he was inside her.
"Hmm, what to do?" She thought