Chapter 5

Justin had just lined his sisters up into a human centipede experiment. It was Tim’s suggestion based on a movie he once saw. A maniacal mad scientist sewed three people mouth to ass into a human abomination. It was supposed to be a horror movie as two women had their mouths surgically grafted to the asshole in front of them. It seemed more like a campy comedy to Tim.

The girls were arranged on the floor with their legs spread wide so that Julie was behind Tyra. Her tongue was in her pussy, and her nose was in her asshole. Justin had just instructed them to crawl forward when his mother wrapped on the door and told them dinner was ready.

A shock wave of chills ran through Julie’s body, and she shivered. She had no idea what she might have said if her mother had opened the door to tell them it was dinner time.

Tyra felt a wave of relief.

She would be able to milk dinner time to take a break from the constant humiliations that she had to endure while obeying her brother. Her only real disappointment was that Tyra had just begun to eat her ass correctly and was twirling her tongue in small circular movements the way she really liked. Tyra made a mental note to make Julie do a LOT of that when she finally won their bet.

“Finally, we get to take a break,” Tyra said as she stood up and wiped the sweat from her face.

“No, you are always to consider yourself a test subject under observation. You will answer to Tyra and Julie and not refer to me as Doctor during dinner,” he reminded them.

Justin made the girls stand at attention one last time while he prepped them for tonight.

He held two white t-shirts in his hand. “You will only wear these in the common areas of the house. You will keep a dildo shoved up your ass unless I tell you otherwise. You will help mom with all chores, clean the dishes and put them away,” he said. Justin spoke slowly because he felt his sisters were not very bright. He gave them some fresh white lace panties to wad up and shove into their pussy as well.

They heard every word but were quite bored and hungry.

“Squat and put your dildo in your mouths,” he said. He frequently made the girls put the dildos in their mouths to lube them up and clean them. It wasn’t something either of them particularly enjoyed. The girls discovered that their spit can be a practical source of lubrication.

“You may masturbate the dildo into your asshole,” he said. He wanted them to thank him. They didn’t as they worked the dildos up their ass.

“Put these t-shirts to walk to the bathroom. You have five minutes to shit, piss and shower together,” he said.

“Five minutes? I can’t dry my hair in five minutes! Much less take a shower, Doctor!” Tyra pleaded. She was notorious for taking long showers. Julie was looking forward to lying in the bathtub for much needed some alone time and letting the gentle waterfall on her puffy, sore pussy.

“You will complete the activity in five minutes, or I will enter the bathroom and punish you,” Justin said. He assured them they would be allowed to take a longer bath later if they were compliant test subjects.

“You will have to budget your time to maximize efficiency. Once you have finished, you must suck your dildo to get it wet, shove it up your ass, and put your shirt back on before you join us,” he said. The girls assumed they would have to do that, but Justin was incredibly pedantic and thorough.

“What if mom or Buddy ask why we took a shower together?” Julie asked.

Justin hadn’t really thought that through. He ticked a checkbox in his notebook to record when his subjects continue to be able to realize the consequences of their actions even though they remain compliant with them.

“You will say that you were saving water. You will be showering together all the time from now on. You will not complain if my research assistants or I enter the bathroom to observe,” he added.

Tyra looked askance at Justin, “Research assistants? You mean Tim is not the only one?”

“Yes, I may introduce you to other research assistants in the course of your observations. You will not mind this,” Justin said the words as if he were conducting a Jedi Mind trick to make the girls less concerned about who watches them bathe.

“I have one last order before you leave,” he said as he tossed the girls their shirts. “You will be sexually excited by Buddy’s voice.”

“Oh, goody gumdrops, “Tyra responded sarcastically.

Their mother’s boyfriend had a deep, dulcet tone to his voice that was incredibly masculine. Julie had daddy issues and didn’t want to admit that Buddy’s voice could be sexy. Buddy talked with a southern accent and frequently made asinine or inappropriate comments.

Justin had no way of knowing any of that. He simply wanted the girls to be attentive and flushed with excitement when Buddy spoke to them. He saw how they rolled their eyes and gave him dirty looks. He wanted to see how they reacted when the sound of his voice made their pussy wet.

When they walked out of the bedroom together, their mother was preparing dinner. “You guys were in there all day. What game have you been playing?” she asked politely.

“Doctor,” Tyra snickered as she and her sister dashed down the hall toward the bathroom. Their shirts barely covered their asses and were even shorter than the ones they had on earlier in the day.

Tami didn’t dwell too much on the idea of her daughters playing doctor. She assumed it was a joke. Tami had played Doctor when she was a little girl. It usually involved a boy spreading her legs and examining her bottom.

“Oh my god, Tyra!” Julie promptly sat on the toilet to pee. “Today was so disgusting. Why don’t you just quit so that we can stop?”

“I’ve been pissed on, pissed IN, swallowed my brother’s cock and spanked. Do you think I’d really give up now?” she said as she slipped the dildo out of her butt. “Scoot over,” she said as she bumped Julie over so they could share a toilet seat.

“Nasty,” Julie didn’t like being crowded on the toilet seat.

Tyra licked her dildo clean as if it was covered in the sweetest chocolate. “Yeah, I am nasty! I am going to play hard. Are you going to put up or shut up?” she dared her sister.

Julie assured her sister that she was going to go all the way as well. It was what Tyra wanted to hear. The longer she could keep Julie playing, the sweeter the reward when her sister finally did give in. In the meantime, Tyra’s wheels were spinning over how she might be able to get her kicks during her brother’s experiments if she could feed her little brother ideas the way Tim had. It was something she was percolating over.

“C’mon Tyra, we need to hurry,” Julie was already wiped and in the shower.

“Or what? Little brother will come in and spank us? You think he would really dare? How would he explain it to mom?” Tyra said snarkily.

“Look, you lose the game if you intentionally don’t obey his orders. If you want to fart around in here, that is on you,” Julie dared her sister to fuck around and find out what happens if she did.

The girls both hurried and took a quick shower. They avoided getting their hair wet. They did remove their makeup because piss had caused their eyeshadow to run down their faces.

They both felt it may not be worth the risk of taking too long in the shower. At the Dinner table, Justin was timing them. He concluded that the girls became less obedient when they were not directly supervised by him. He had also noted how poorly they trimmed the grass outside. It was patchy, and some areas, the girls, clearly trimmed the grass down to the nubs while others they ignored completely.

Once they were ready, they pulled their shirts down as far as they could go to cover their legs. The hem of the t-shirt barely came up to the tip of their pussies. Julie’s dark pubic hair was visible hanging down between her thighs.

“You really need to trim that bush, Sis,” Tyra teased her. “If Professor Goober doesn’t make you trim it, I am going to make you shave it completely bald. Brad Miller likes girls with hairless snatches, smooth as a baby’s bottom,” Tyra slapped her own well-trimmed pussy as she said it.

Julie inserted the dildo up her ass and nodded.

“It’s not like he is going to check during dinner,” Tyra scoffed.

“If he tells you to do something and you didn’t do it, what are the chances he’ll figure out that you were playing him? What did you say happens if he stops the game because he thinks we are just playing with his head?” Julie reminded Tyra that they had to obey.

Tyra didn’t question it. She slipped the dildo into her mouth and down her throat to slick it up, then she pushed it up her ass. Her pained expression suggested that even as experienced as she was with anal that it wasn’t pleasurable to constantly butt fuck herself.

On the way out of the bathroom, the girls giggled and joked which each other. They were making fun of Justin and Tim. It wasn’t unusual for them to do that, but they wanted them to hear it.

Tyra had a ready excuse for the delay to her brother. He had explicitly told them to take five minutes, and they didn’t do that. “Sorry, it took us so long to wash up. We underestimated how long it would take,” she smirked her apology. Tyra didn’t directly address Justin. It was more of an open statement for why she had missed the first fifteen minutes of the meal.

“Oh, that’s okay, we were just talking about your game,” Tami said to her daughters. Their meals were already on the table, and Justin had mixed up some more tea. It tasted gross, but compared to piss, it wasn’t half bad.

Julie’s asshole puckered and squeezed the dildo she packed into her ass tightly. Her entire spine shook in trepidation, wondering what Justin and Tim had told their mother.

“Oh yeah?” Tyra was a much better liar, and she was cool as a cucumber. She was a little worried about what her brother might have told her mother, but it didn’t show on her face as she sat down.

“Yeah, I was shocked when he told me. You are helping Justin with a school project. I really thought he was kidding,” she said.

“Oh, that,” Tyra seemed confused and apprehensive, but she played it off like helping her brother was no big deal. It would be a first for her or Julie. They rarely even associated with Justin.

“They are helping me formulate my hypothesis on human behavior and systemic modification of attitudes and values through the inclusion of external stimuli and psychotropic mood enhancers. If successful, I can chart a spectrum whereby some behaviors are common while others unusual, and some are acceptable while others beyond acceptable limits. The acceptability of behavior depends heavily upon social norms and is regulated by various means of social control, partly due to the inherently conformist nature of human society in general. Thus, social norms also condition behavior, whereby humans are pressured into following certain rules and displaying certain behaviors that are deemed acceptable or unacceptable depending on the given society or culture, but through manipulation of that continuum, we can overcome that inherent programming,” Justin explained as if what he just said was easily understandable to a layman.

He had clearly baffled everyone with some scientific-sounding technobabble. It made sense to Justin, and it was technically true on some level.

No one understood a word of what he said, and most didn’t pay attention to all of it. Justin was used to that reaction from his family.

“I am helping,” Tim added casually and offered a cocky smirk.

He introduced his sisters as Test subject A and Test Subject B. “Scientific principles dictate that I objectively consider each subject in my simulation. It helps maintain objectivity by addressing them that way,” Justin said.

“Well, I’ll just call them Julie and Tyra at the dinner table if that’s okay?” Tami laughed.

“Perfectly acceptable,” Justin added, “The testing continues at all times – even when out of the lab.” He turned to his sisters at the table and told them that they would respond to test subject A and test subject B in the common areas. Justin spoke in a calm but patronizing manner like he was talking to a simple-minded person.

“The lab? That’s cute,” Tami chuckled as she drank some tea.

“Does that mean we should call you, Doctor?” Tyra offered him an impish grin. Buddy laughed out loud and then stopped when he realized she was serious.

Tami didn’t understand Justin very well. She knew he was a bright-minded kid and had aspirations to be a scientist one day. She didn’t like it when his older siblings teased him.

She was willing to humor his strange research project, and it seemed like they were too. Tami didn’t see any harm in it even if it did sound kind of strange to her.