"Just a test of obedience, nothing major." The grin turned a little sadistic "Head out into the back right now, stand facing the house in the centre of the lawn, and put your hands on your head."
Tony blushed, wheels in his desperate, horny, mind turning. "Can I--" he began to ask as Alex put a finger on his lips to silence him.
"If you're asking about getting dressed first, no. You're going to piss and cum naked in the garden. Oh, and be sure to catch as much of your cum as you can. You might be outside for a while, and I wouldn't want you to get burnt. I'll make sure to turn your cum into something that works as high-factor protection. Because I'm nice, I'll even let you keep your cock and balls for a while, so if you feel like you need a top-up, you can apply some more."
Alex turned towards the computer, as Tony stared at his brother in horror at what he was being asked to do.
"I'd start moving if I were you unless you want me to make it your piss that acts to protect you from getting burnt?" Alex chuckled, then paused, wrinkling his nose in disgust at a thought passing his mind, before adding almost as much for himself as for Tony "...Or your shit..."
Tony practically ran out of his brother's door as he heard him say that. Alex, meanwhile, started programming the changes into the Chronoviac, timing it all for a specific trigger, before a few minutes later meandering down the stars, towards the back door, looking at Tony staring at him through the glass, exactly as he asked his brother to be. He locked the door, and Tony's cock and balls grew back, as he grabbed his cock, and began watering the grass with his piss.
Sighing with relief - the sensation of emptying his bladder after being absolutely bursting for over an hour would have been pleasurable even if he wasn't also insanely horny at this point, and as the stream tapered off, he remembered what Alex had told him about being out for a while, and positioned his hand to catch as much cum as he could, and came to the biggest orgasm of his life, producing an inhumanly large load thanks to Alex's modifications.
In his post-release state, Tony shuddered at the thought of what he was about to do but began rubbing his cum - which Alex had done nothing to change the smell or texture of - into his skin. He looked towards the back door and saw Alex giving him a thumbs up. He internally groaned - regretting deciding to make himself desperate and incapable of bringing himself relief in the first place.