Johnny looks quickly around the room, and quickly performs the spell as best he can. Having watched her do it so many times was one thing, but weaving it into another of his shrinking spell so he ended up the appropriate size was an entirely different matter.

Focusing with incredible self-control, Johnny clears all other thoughts from his mind except that yellow crescent shape and slowly becomes aware of not only thinking it but being something new altogether. Feeling pleased with himself, he waits an opportune moment to surprise his girlfriend.

Jenna walks into her room and dumps an armful of books onto her bed with little regard for their well-being. With just as much delicacy she plops herself down onto the bed next to the pile and sighs wearily. Her eyes are closed and her guard is down. Johnny could not have asked for a better setup!

Unfortunately for him, he finds himself unable to revert back to his original form. Again and again he frantically tries to no avail. Trying to calm himself, he begins mentally reviewing the steps to the metamorphosis spell but is interrupted by the loud growling of Jenna's stomach which shatters his concentration like the surface of a pond with an elephant doing a cannonball into it.

Meanwhile, Jenna sits up and looks around her room. Something seems slightly amiss, but she can't quite put her finger on it. She shrugs it off and guesses (even more correctly than she could know) that whatever has changed is due to her boyfriend Johnny, to whom she smuggled a key so he could visit her. 
Getting up and walking over to a bowl of fruit she keeps on the dresser, Jenna idly inspects the contents while thinking fond thoughts of her sweetheart. Picking out a banana to satisfy her hunger, she walks back over to her bed and lies down again. "I'm surprised he wasn't waiting for me! I haven't been able to get a moment to myself ever since I showed him how to use that spell..."

Jenna begins to peel the banana and smiles mischievously before adding "Not that I mind that at all..." Jenna giggles and daydreams for a few moments. From the look on her face, it's obviously something that would turn the writer of Barney white as a sheet. Another groan from her stomach returns her attention to the task at hand. Jenna stares at the banana for a few moments before saying "You know banana, you remind me of my boyfriend for some reason. Though I can't say why... but it's not your size, that's for sure! XD" She giggles to herself as her mind drifts back toward her fantasies for a moment.
She shrugs and says "Well, I guess I'm just feeling lonely. I guess you'll just have to keep me company until he gets here." She says before giving the banana a large kiss on the tip with her luscious lips before sucking it into her mouth and biting off a piece. 

Chewing slowly, her glands salivate heavily from her tongue's happy exploration of the flavor in her mouth. Dually enjoying the squishiness of the soft fruit, Jenna grinds away at her food gradually. Eventually there's nothing left to chew and Jenna allows the slimy mess to slide into the back of her throat where she easily sends it down into her belly with a contraction of her throat. 

Jenna takes and finishes another bite with much pleasure, then pauses. Glancing around her room to make sure the window and door are closed, she commences to sensually lick the rest of the banana. Smiling wide, she inserts it deep into her mouth, covering it in as much spit as she can to help slick it up. 
Gently she rocks it in and out of her mouth, pushing it a little farther each time. Eventually, she starts pushing the tip into the top of her gullet, which eagerly grabs at the tip which is too slick to keep a good grip. 

Jenna removes the banana from her mouth completely for a moment and inserts her middle and index fingers on her other hand instead. From there, they come out and head toward her hips as the banana resumes it's bobbing in her throat. Jenna's throat is soon filled with grunts and groans of pleasure besides as she slides the banana deeper and deeper.

Without thinking, Jenna shoves the banana deep into her throat and swallows tightly, pulling the entire thing into her esophagus. Pausing only to discard the peel with a casual toss Jenna continues to pleasure herself and recruits her now-free hand to massage her breasts as the banana slides  down into her stomach with a "sploop!"
Completely engrossed in her masturbation, Jenna doesn't give the banana a second thought as her tummy churns it's soft body into nutritious mush. Her stomach in full swing pumping out acid to digest her meal, by the time Jenna climaxes and messes her panties the banana is already being squeezed into her small intestines where her body begins absorbing bits and pieces of it. 

With nothing to do except wait for Johnny, Jenna decides to take a cat-nap. Her breathing slows, she stops moving, the only sounds that can be heard are deep in her body which remains quite active as it processes her food.

By the time Jenna wakes up, her body informs her that she's digested a significant amount of food. With a little fart, Jenna tries to ignore the urge as she tidies up her room a little, Picking up the books she so carelessly scattered onto her bed which are now scattered on the floor.
Jenna's rectum will not have it though, and within the next sixty seconds, Jenna gives in and makes her way to her bathroom. Slipping her wet panties down around her ankles, Jenna nestles the bare cheeks of her butt onto the seat of her toilet. 
Exhaling, Jenna relaxes her rectal sphincter and the tip of her turd begins to protrude from her anus. As she contracts her rectum, her anus lips stretch tight around her feces as they are squeezed from her ass. Jenna continues to poop out the contents of her nether-regions until her rectum is once again empty. 
Immediately thereafter, Jenna pauses and begins to empty her bladder into the bowl as well, her thick stream of urine churning the water a deep amber. Jenna finishes up, wipes herself delicately with several patches of toilet paper, then drops the soiled cloth into the toilet before standing up, her cheeks meeting one another again. She slides her panties up around her butt once more and flushes the toilet before returning to her room.