His sister is waiting in his room.

K-T quickly showered and was glad to be rid from the smell of cum. He didn't even consider wearing the things he had on coming back home. He was about to put them in the hamper for dirty laundry, but he realized that with his luck he'd probably end up with only this to wear at the worst moment one day, so he put them in the trash instead.

Everyone in his family had their own towels and his sister had made it pretty clear that she would kill him if his dick went anywhere near hers. For some reason his mom always bought packs with small and large towels and he always ended with the small ones. Ones so small that he could not wrap them around his waist without holding both ends in one hand to keep them in place. With his room barely two doors away from the bathroom and his mom not being at home he decided it wasn't worth the hassle to bring a wet towel to his room. He just looked both ways in the hallway, saw that no one was here and that only his room's door was open before dashing to it.

He slammed the door behind him and when he turned around to start looking for something to wear, his sister Emily was sitting on his bed with a big smile.

"Emily?! What are you doing here?" he screamed. "Get out, I need to find some clothes."

"Nonsense, you had the right idea being naked in the first place, brother." She countered.

"What are you talking about?"

"Listen to me. Starting now, I own you. Not only am I in charge of your treatment and I am the one to decide how humiliating it can get for you, but I also have the video of your little show of this morning. I'll blur everyone's face but yours of course, but if you don't comply you will become an instant start on any porn site that I can find. You will be known worldwide as the dude cumming while having his temperature taken."

"It's not my fault, I couldn't hold..."

"Rules. Starting now you are only allowed to wear what I tell you to wear, when I tell you to wear it. If mom asks why you stay naked at home, and let me tell you that you will be naked at home, you will tell her that it is exposure therapy for the first phase of the protocol and that you need to spend as much time naked as you can until you no longer get excited by it." She explained.

"Please, I'll do what you want, just let me me wear normal clothes at school. I already get into enough trouble as it is, I don't need everyone to think I'm some sort of pervert because of what you make me wear." he pleaded.

"We'll see. Besides, considering your treatment and the possible side effects we might not even have a choice. And they won't need your clothes to think you are a pervert. You are hard again after what happened, just from standing naked in front of your own sister." She laughed. Something startled in K-T's brain. He wasn't hard again, he was still hard. It wasn't unusual for him to stay hard for a bit even after an orgasm, but it would have gone down by now. He had waited probably half an hour in the waiting room and probably as long of a drive back home and then took a shower. His lower member should have normally went back to its softer state. Yet it remained hard and pointing up. His sister saw the shock on his face and quickly made the link.

"Wait... You have not gone soft?" she asked him.

"Well, not yet no. I sometimes takes a while to go down but it's been very long now..." explained K-T blushing even more than before. Something he realized was that he had not even made any attempts to hide it from his sister. His fear of disobeying his mother's orders to follow his sister's instructions had completely made him forget that he should try to cover himself.

Emily took her phone out and took a picture of his cock, before typing something.

"What are you doing?" he screamed.

"I need to document your participation in the trial. The doctor gave me an app where I can log pictures and notes on your progress. I'm just noting that there is a high probability that you are suffering from permanent erections. Any other issues? Soreness, sensitivity, pain? " she asked him.

"No, it just doesn't go down." said K-T. He wasn't truly honest as he had noticed his ballsack being a bit looser than usual but he wasn't sure if it was something permanent and it wasn't pronounced enough to be sure if it was really a side effect. "Who has access to those pictures, by the way?"

"Just the doctor and her team so that they can collect data. Oh and probably the review board that will check the validity of Dr Conners research. After that it will be archived and will only be accessible to doctors and students in the medical field, or someone with a subscription to the professional medical journals that Dr Conners will publish the research in. This is medical data, not some of the porn you watch, those people don't care about your cock, only about the **** and its effects."

"Still, that's a lot of people. How often do you need to take pictures?"

"After each treatment, we might have to hold a ruler next to it in the future."

"Why? It shouldn't do anything about the size of it, just stop me from... You know..."

"They had contradictory data when they tested it on rats but it was hard to tell because of the size. There is a very small probability of the constant swelling making it permanently bigger and an equally small probability of the overextended tissues shrinking massively once the engorgement stops. We are talking in less than a tenth of a percent chance here, but I'll need to document it."

"I wasn't told about this!"

"She only told you the list of the most probable side effects, there always some rare edge cases. Anyway, I'm hungry and I don't feel like cooking. Mom left me some money, let's order a pizza."

On that, she left him alone in his room. She had left the door open going out, but since it didn't lock and she would enter whenever she wanted K-T felt pointless to go close it.

It would not have been the first time he'd spent an afternoon naked in his room. Only this time he had access to his clothes, he just couldn't wear them without disobeying his sister. In a sense it was even worse than when he often found himself without anything to wear.

He just sat at his desk and launched a game to pass time before lunch, only stopping when he heard the door bell ringing half an hour later.