Yes, among other things.

Jace panted heavily as a welcome beep told him he'd finially finished the 30-minute run Mari had set him, stumbled off the treadmill, and slumped against a wall near the rowing machines.
Despite his exhaustion, he was surprised he'd made it the whole time, usually when he tried these things he'd have to take a break partway through. On the other hand, at least he wasn't aroused anymore. Heading for the showers, Jace passed Mari again. "Hold up, 24793, you have to do some stretching, otherwise you'll barely be able to stand tomorrow." Mari waved him over to a mat and began guiding him through some basic stretches. Her gentle touches as she repositioned his limbs when necessary had him fantasizing about what other limbs she could touch, and he was half hard again before they were done.

"Thanks, Mari", he said as he headed for the showers.

Jace glanced around the shower area and frowned slightly as he realized one of the "top 5" was flaunting his physique in an open stall. In the jizz-volume rankings, the top 5 men held a privilaged place, as they were among the few who could get it up more than a couple times a day, making them in high demand among the staff when they wanted the real thing even if it didn't match their fantasy desires.
Jace's mind dove down another tangent - Luckily for the lucky (in some respects) few really large porn stars out there, the nanotech had also caused women to stretch more easily and recover more quickly from it, not to mention strengthening the average vaginal muscle tone. But the same changes meant women experienced more pleasure from larger cocks, essentially making 99% of women the size queens some pre-nanotech porn fantasies imagined them as. Even though men like "Long Dong" couldn't actually get it up more than once a day, the sheer size and output of his equipment meant any woman who he fucked for a scene would experience incredible amounts of pleasure, especially when she literally started being inflated with cum. This ensured an unending supply of women willing to sign the necessary NDA's. Also, th...

"Hey, stop staring at my cock, what are you, gay?!?" a growl from the other end of the room jolted Jace out of his mental tangent, and he realized he'd been staring blankly through #245, ranked 5th by volume and quite willing to lord his status over anyone he could.

"Sorry man, I was lost in thought", said Jace, heading for the opposite end of the shower area and closing the stall curtain behind him.
"That's right, I don't want to see you jerking your tiny dick, if you can even get it up again after Lily visited", jeered #245. "One of these days I'll convince her to give me a shot", he went on.

"Not a chance", Jace returned from in the shower stall, "you know her one true love is that custom Long Dong she's got in her room, we normal men just don't measure up" (Lily's status as the biggest size queen on the staff was well known, if not discussed in front of her, ever since Chad "Asshole" Wilson had peeked in on her one day when she was taking a libido break. He still maintained that he'd been worried she was hurt, but no one believed he'd been able to mistake the screams of pleasure as the attached pump filled her with faux cum for anything else. The tale still spread through the facility though.).

The showers in MES were fitted with soap dispensers activated by a microchip implanted in the wrists of subjects - it kept track of their various individually tailored consumables, including shampoo and body wash tailored to each individual, not to mention the more specific "cock gel" and "cock cream (the jokes never ended, even though they were all old by now)" which subjects were strongly encouraged to wash their genitals with and massage into the same after cleaning themselves.
Something about improving blood flow and preparing the skin for stretching, Jace vaguely recalled. Not that anyone had need of the latter yet.

Jace undressed and placed his sweaty workout clothes in a waterproof laundry receptacle in the stall wall, then selected one of the offered options from the "casual" menu on the touchscreen controls - fresh clothes fitted to him would be ready when he was done, and for all he knew, his sweat would probably be analyzed for yet more data.

MES were nothing if not thorough, but they allowed their volunteer subjects at least some privacy, if only because early trials had proven it was necessary for any kind of progress.

So far as Jace was aware, there were no cameras or other monitoring systems in the showers, apart from measuring water use, time spent, soap usage, and of course the sweat left on clothing.

As a result, he wasn't concerned when the relaxing shower led to an actual second erection for the first time in a decade, he just went with the flow of his fantasies. Closing his eyes, Jace imagined he was standing behind the VR Lily again, preparing his cock to impregnate her.

Rubbing his massive cock with both hands as he prepared to inflate her with fertile sperm from his huge balls, ensuring she would carry his child.

He'd always had a vivid imagination, and he could even feel the fantasy between his hands this time, feel the imagined balls brushing against his legs, churning with cum just waiting to be unleashed.

With an explosive grunt, Jace ejaculated against the shower wall, keeping his eyes tightly closed to prolong the fantasy, Imaginary blasts of cum splattered against the wall, unloading from balls bigger than his head, flooding the shower stall as it overwhelmed the drain, filling the shower until it reached his feet..

What the fuck?!

Jace's eyes popped open and he saw it wasn't a fantasy, his cock was so large it nearly touched the shower wall, so thick his hands couldn't touch if on opposite sides, and there was so much cum he worried it'd escape the showe...

His stunned thoughts were cut off by a another blast of cum which plastered the shower wall, covering the laundry controls this time.

SHIT!, what the hell is going on, how did this happen, where the hell did this huge log of flesh come from, and why was he so light-headed?

He glanced at his body and was stunned to see that barely an ounce of fat remained. His body looked as if it'd lost some muscle mass as well, and he looked like a scrawny teenager attached to a cock as big as his newly thin thigh.

Apparently that was where the huge log of flesh came from, he thought drowsily, as he slumped limply to the floor atop his softening cock.