(Note: Yes, I'm combining things from several other routes. For example, the Auto-Reset coming from the route where he becomes his girlfriend's diaper)
Jeff suddenly reappears back in his room, Reverted back to normal. "Huh? I'm back here" Jeff thought... "Wait, I can get Jess back for this!" Jeff immediately gets on the Chronivac and changes the settings; Name: Jess, Transformation: Diaper, Auto-reset: On, Mode: In-Place, Timer: Every 2 hours, Communications: On, Mode: Telepathic, Absorbancy: Maximum. "Now she gets to feel what it's like to be a diaper. I get to hear her deal with what I had to." Jeff thought "And... Activate."
Jess suddenly felt a tingling sensation, then shrunk down, turning into a diaper. "What the?!" Jess screamed, although nobody could hear her. Jeff then walked into her room, and picked her up. "Hello, Jess. Enjoying being a diaper? You'll be Nina's diaper for a while.." Jeff said, focusing his thoughts on Jess. He then walked over to Nina, who was already wet again. He immediately took the diaper off of her, cleaned her up, and slid Jess under Nina's private parts. "Oh no! no no no!" Jess thought, knowing she was going to have the same fate she gave Jeff. However, little did she know, she was gonna have it worse... She wasn't gonna be used once and tossed aside, she was gonna be reused over and over again. And, She doesn't know that Nina can use her however much she wants without feeling it...
As if on cue, Nina's vagina opened, using Jess already. A large torrent of pee comes out, making Jess expand a little bit to hold all the pee, however still still allowing Jess to easily absorb it all... "I wonder, how could I make this worse for you Jess? After all, you clearly didn't care when you tossed me out, so I don't care how bad this is for you." Jeff thought, focusing on Jess again. "Actually, Instead of a diaper... I know what I could do."
Jeff grabs the Chronivac out of his pocket and changes some settings; Setting Jess to where she's a pair of pajamas, keeping a diaper attached to them so she doesn't transform and already be completely soaked, and sets it to where she's a perfect fit for Nina. He also makes sure it's set so that she can feel everything; Inside or outside of the pajamas. He then sets it so that the diaper part resets at 8:00PM rather than every two hours, so she resets just in time for Nina to go to sleep. "You better enjoy this, Jess..." Jeff says, still focusing on Jess. "After all, you'll be stuck like this until Nina's out of diapers... Then you can be like her underwear or something." Jeff then activates the Chronivac, and Jess then starts transforming, fitting right around Nina's body perfectly...