The state of euphoria the two older teens were in was bliss for sure as the two were cumming, and at that state the Chronivac's changes started to affect the two. Step 1: Reinvigorate the two teens. Jenny had enough foresight to imagine their initial "exercise" may be a little exhausting thanks to their reckless enthusiasm. Even if it wasn't that bad, why not feel fresh for Round/Step 2?
The two teens were clean as their sweat and body fluids were reset, and Jeff's penis was now just as hard as when he had started instead of the bit of the limp thing it had been after round 1. The two started making up with Jeff groping Jenny's breasts again, but Jenny asked "This time, could I be on top?" Jeff wondered if this had anything to do with the change, but decided that regardless it would be fun.
As Step 2 was starting, Jenny mounted herself on top of Jeff's hard girthy member. She moved her hips back and forth as Jeff thought to himself how great this was. Just having sex and refreshing themselves constantly would be a fun treat. Jeff was lasting longer this time, and had a fun time watching Jenny's breasts jiggling. However, as it was progressing, Jeff wondered if he wasn't as deep in Jenny, while at the same time he felt more weight on his chest. The weight just felt like it was getting heavier, and... did something just enter his crotch?
Jeff looked down at his torso and saw some seemingly decently sized breasts that seemed to keep growing, and a moderately thin waist that seemed to be getting thinner. However, at their crotch, he saw that Jenny was now wearing a purple strap-on that was penetrating him! Going by just feel, Jeff was sure that Jenny’s auxiliary appendage was getting bigger and thicker. Jeff was processing what was going on, but putting it together while getting fucked was quite difficult.
By that point, Step 2: Gender Bender had ended, and Step 3: Clean Up began, leaving Jeff and Jenny to bask in the afterglow without having to worry about the general mess.
Jeff, laying next to Jenny, peeked beneath the sheets and examined herself. Her breasts seemed to overfill her dainty hands. Her body was smooth, soft, and hairless, and a small pat downstairs confirmed she didn't have a dick anymore.
Jenny purred and said, "You know, I was wondering if I gave you too much or little on top. Think I got it about right. Wanna take a peek at my ‘junk?’” as she held up the strap-on. Jeff blushed a bit as she saw just how big it really was...
"That FIT in ME?!?!" Jeff squeaked out in her cute little voice.
Jenny nodded and said "Yeah, figured I'd see if I could make both my toy and your insides a bit bigger."
Jeff sighed and said, "Well, I think I'll go take a shower, we're clean but I'd like to feel the water..." and jumped out of bed and noticed everything looked significantly bigger. "How tall am I?"
"Four foot eleven."
"...how tall are you?"
"About five foot six. I wanted to see what it'd be like to fuck someone smaller than me." Jenny got out of bed as well, and stood next to Jeff, which instantly showed the distance between the two. Being such a small girl, Jeff couldn't help but be intimidated a bit. Though not easy for her, Jenny was able to pick up Jeff and carry her into the bathroom like a princess. “For Step 4, I changed the bathroom a bit to have a nice large tub. How about we soak and talk a bit?”
After a setup, Jenny went in and Jeff came in right after, at which point Jenny said "Well I enjoyed how things ended up, how do you feel though?"