Conditioned Response

"I'll get rid of that," he said quickly.

Maddie turned and looked at him. She couldn't figure out why he looked embarrassed. When he took the small wastebasket to the garage to empty it into the larger garbage bin, she went to the kitchen and found a can of air freshener. It took Todd a bit to find a replacement trash can liner, and when he finally returned to his room he nodded as he sniffed the air.

"Wow, that's a huge difference," he said.

"Much better," Maddie agreed. She was lounging on her side in his bed. She patted the mattress, and he sat down. He turned to face her and leaned back to a more comfortable position.

"So, what happened to you today?" Maddie prompted.

"I..." Todd blew out a breath. He had intended to say he didn't want to talk about it, but instead said, "I ran into Jasmine today—and her new boyfriend. She gave me a nasty look and hugged onto him to make a point."

"Oh," Maddie said. She gently reached out and rested her warm hand on his thigh. "I'm sorry, Todd. I thought you two would get back together." Her hand gently rubbed his thigh. "That was partly why I thought it might be a good idea to clean up in here."

Todd blew out a breath. "I'm afraid not," he said sadly. "She just couldn't forgive me."

Maddie's hand stopped. "What did you do to her, Todd?"

He was embarrassed. There was no way that he could tell his sister what had happened. Todd shook his head.

"Did you hit her?" Maddie asked, her voice almost a whisper. She couldn't imagine her brother doing that, but it was the only thing she could think of that would be so unforgivable.

"No! Of course not!" he protested. Todd looked up at the ceiling. He could not believe he was telling her this. "Jasmine was here, and she was sucking my dick."

"Okay," Maddie said slowly. Her hand resumed slowly stroking his thigh.

Todd's head snapped down and he looked at his sister's face. It was tough to tell through those shades, but she didn't seem fazed. He realized uncomfortably that his sister was now lying on his bed with her face not far from his crotch, just as Jasmine had so often. He shook his head to clear that thought and forced himself to go on.

"I put my hand on the back of her head and forced her down on me," he said, blushing. "I was thrusting up into her mouth, and I made her swallow it when I came."

Maddie's hand continued its stroking motion on his thigh, and Todd was aware that it was getting closer to his shorts with each stroke. Abruptly, she stopped her hand and cocked her head.

"That's it?" Maddie asked.

Todd choked a bit and nodded. He had really expected her to be shocked. It shocked him that she reacted the way she did, just taking it in stride so casually.

"I told her I was sorry," he said softly. "I just got caught up in the moment and couldn't hold back."

"I—" Maddie shook her head and looked at the wall thoughtfully. She had almost blurted out "I thought she liked that." She thought for a moment before saying, "I just thought you two were closer than that. It doesn't sound so bad that she should have broken up with you over it."

It was all she could do to contain the "In fact, it doesn't sound bad at all," that she wanted to add to the end of her statement. She was moist as she pictured Todd doing that to her, imagining his hand on the back of her head as he forced her to swallow his delicious sperm.

Her gaze returned to his crotch, although he couldn't tell. Her hand was so close to that tasty cock now. Her mouth started to water as she imagined pulling it out and sucking on it again. She could not hold back her soft moan when she noticed his cock hardening right in front of her.

Todd swallowed hard. "You really surprised me, Maddie," he said softly. "I thought you would be shocked. I couldn't imagine that I could tell you what really happened."

"You can tell me anything," she replied. Her face was so close that her breath went right up the leg of his shorts. Todd could feel that warm, moist air on the sensitive tip of his dick. He realized to his horror that he was sprouting a boner right in front of his sister's face.

Maddie's eyes glazed with desire as she watched her brother's hardening cock throbbing right in front of her. It was pointed down the leg of his shorts. As it stiffened it also rose upward from his leg, lifting the soft material with it. She licked her lips and breathed heavily. Each breath washed over his cock, stimulating him further.

Todd knew that he had to act or she would definitely see his hard dick. He groaned and rolled away from her, off of the bed. Facing away from his sister, he smoothed the front of his shorts, striving vainly to hide his obvious arousal. That action snapped Maddie out of her stupor, and she blew out a breath before she slid out of her brother's bed.

"Maddie..." he started.

Maddie wrapped her arms around his midsection from behind, hugging him. "It's okay," she said. "I'm glad you shared that with me. Do you feel better?"

Todd felt her soft breasts pressing into his back. He blew out a long sigh and realized that he did feel better—just awfully horny as well. "I do feel better," he said, resting his hand on her arm. "Thanks for listening."

She squeezed him for a moment before letting go. "Any time," she breathed into his back. She brushed by him and walked out of his room.

Todd thought he caught a whiff of aroused pussy, but when he sniffed the air all he could detect was the air freshener. His eyes were glued to Maddie's soft round bottom as she walked away. I always assumed she would have a bony ass, he thought.

* * *

Their parents returned from work not long after that, and Todd helped his mother prepare dinner. He was shaken after having his sister in his bed earlier, and did not trust himself to be around her. He was afraid of popping another boner where the whole family would see it. When they ate, he sat across the table from his sister.

After dinner, Maddie removed the dark shades and let her eyes slowly adjust to the light. She still had to squint to keep her eyes from hurting, and she really wasn't supposed to squint. She put the shades back on.

"My eyes are a lot less sensitive, though," she said. "I'm sure I won't need these things by this time tomorrow."

"Oh, man. I totally forgot," Todd blurted. "I was invited to a party tonight." He looked at his watch. "I've still got time," he muttered to himself as he went to his room to change.

Maddie watched a television show with her parents, and then she excused herself to go to bed. She brushed her teeth and changed into her normal snug t-shirt and panties before sliding into bed. She was tired after that relatively long day. She fell asleep with a smile on her face, already dreaming of her brother's hard cock.

When Todd came home at one in the morning, the sound of the front door woke Maddie. She listened to her brother as he removed his shoes and walked softly through the house. He wasn't loud; she was just keyed up. Maddie wanted to suck him again and her mouth watered at the thought.

Prior to this past month, Maddie often lay awake deep in thought. She contemplated questions of cosmology, like how supermassive black holes could have formed right after the Big Bang, what could be the source of extra gravity that was labeled "dark matter", or what could be causing the accelerated expansion of the universe. She would imagine herself as a character in one of her science fiction shows and think how she would have reacted in those scenarios. Now, she watched the clock and estimated how long she would have to wait before her brother would be deep in REM sleep so she could suck his delicious, throbbing cock.

She listened to him go into the bathroom and marked the time that he returned to his bedroom. It would take him four minutes or so to undress and go to bed, she thought. It would probably take him another fifteen minutes to fall asleep. She frowned slightly. Where had she come up with that number? She started poring over the sleep study data in her head and realized the range was far more variable.

After fifteen minutes, she slid from beneath her covers and sat in front of her computer. A few mouse clicks later, she was peering at the dim image on her screen. She could hear her brother's soft snores coming through the headset and allowed herself a small smile. He was asleep. He was also not wearing a shirt. She killed the remote access and got up. It was time to get what she needed.

Todd was sound asleep when she reached his bedside. His body was under the covers this time, except for his upper chest and head. Maddie watched his face carefully and listened to his breathing. When she was satisfied that he was unlikely to wake up, her trembling fingers finally lifted the covers. She let out a soft sigh when her eyes took in his swollen erection.

Todd moaned softly when her hair brushed over his thigh. He felt even bigger tonight when Maddie took him into her mouth. Once again, she savored the taste of him as she began to gently suck more and more of that hard cock. "So good," Todd breathed again, and Maddie shook helplessly as her pussy spasmed in response.

After a few minutes of her gentle cocksucking, Todd's hips began to push upward into her face. Maddie did her best to keep her moans quiet, but it was really getting her off to feel him fuck her mouth. Suddenly, Todd thrust upward harder, and Maddie gagged. His cock drove into her throat three times in rapid succession, and she pulled off of him. It took an effort of supreme will for her not to vomit.

At the same time, her legs were shaking as her pussy exploded in orgasm. She curled up on her knees next to the bed, shaking uncontrollably for several seconds. When her nausea passed, she rose up on her knees to look at her brother's face.

He was still asleep, moaning softly. His buttocks flexed, pushing his erection upward. Maddie reached out and wrapped her hand around the base of his thick shaft. Her eyes went from his cock to his face a few times, and then she crawled over her brother's leg to kneel between his spread thighs. She had to have it back in her mouth.

She kept her hand on him as her mouth once again engulfed that tasty cock. She moaned softly as she slurped down all the delicious pre-cum that was oozing out of him. It was impossibly arousing to her every time her brother bucked his hips upward. She managed not to gag, but she wasn't taking him in her throat. Her hand wrapped around the base of his shaft gave her some control.

Todd did not last long before he groaned in his sleep once more and filled her mouth with thick cum. "So good. Oh, so good," he moaned softly. Maddie trembled through another shattering climax as she drank her brother's sperm. After she had taken every drop of it, Maddie worried that Todd was waking up. She carefully got out of his bed and retreated to her room.

Maddie lay in her bed for a while, reliving this most recent encounter. It had been so amazing, except that her reflex to gag had almost ruined everything. She got out of her bed and onto her computer. Naturally, the parental controls made it impossible for her to find the information she wanted. Any search on "gag reflex" produced tens of thousands of blocked results.

It would be child's play for her to disable the parental controls, but Maddie knew that doing so would instantly send a notification to both of her parents' cell phones. She would need a cover story before she tried that. Then another possibility came to mind. She could use one of the on-campus computer labs for her research. Those computers did not have any sort of filter. She would just need to be careful to find a lab where she could use a computer that gave her a degree of privacy...

Her mind quickly reviewed the layout of five computer labs she had used over the past year and a half, and she immediately thought of "the perfect spot."

* * *

The next morning, Todd was in a really great mood. He readily agreed to drive his sister over to the campus so that she could "do some research" at one of the computer labs. "I should only need two hours to study," Maddie told him.

As they drove across town, Todd said, "You know, you should really get your license. I wouldn't mind letting you borrow my car for stuff like this."

She looked over at him. "That's really generous of you, Todd. Thanks." Maddie could not help but smile at her brother's happy face. "You're in a really good mood today," she said.

"I had the most amazing dream last night," he said, shaking his head softly.

Behind her blocky shades, Maddie's eyes went wide. "Oh, really?" she asked.

"Yeah...it's a shame I can't remember any of it, but I woke up feeling incredible."

Maddie blew out a relieved breath. Soon after, Todd dropped her off at the computer lab. "I'll be back, right here, in two hours," he said.

"Thanks again, Todd!" she said as she got out of the car. "I really owe you for this one."

Todd could not help but stare at his sister's shapely bottom as she walked away from him.

* * *

Maddie's search led her to an unreal number of pornographic web sites. Most of those required a credit card to access, and did not look like they would be helpful. She was aware that there was a lot of pornography on the internet, but she had never had any interest in viewing it before. Finally, she found some links that looked promising.

Her mouth dropped open when she saw her first ever porno, featuring a young woman "with no gag reflex." Her pussy drooled when she saw this girl getting face-fucked by a nice thick cock that looked an awful lot like her brother's. That cock was attached to an older, hairy, overweight man, but it was still like watching her personal fantasy on video.

When it finished playing, she shook herself out of her cock-induced stupor and saved the video to her thumb drive. A search of that website turned up some videos on "gag reflex training" and several of those actually looked helpful. She saved seven such videos to her thumb drive. After that, she found dozens more videos featuring women getting their throats fucked by cocks of various sizes and shapes, and she looked around the room often as she saved video after video to her thumb drive.

She left the computer lab and went to the ladies' room, thrashing her horny little pussy until she came twice. By the time Todd returned, she had a very good idea what she needed to do to get rid of her pesky gag reflex.

Back at the house, she locked herself in her room and watched all of the "training" videos. Three of those were the most helpful. They all featured young women who had made video diaries as they worked larger and larger phallic objects into their throats.

Three others featured young women who gagged as men forced them to take their dicks down their throats. One of those girls actually threw up on video, making Maddie glad that she had not done so the previous night. The other video featured a middle-aged woman who was getting similar treatment. In all four, the women gagged repeatedly but were finally able to control their gag reflex so that the men could bury the entire length of their cocks down the women's throats.

That will be me, Maddie thought as she watched one young woman with her nose pressed firmly into the guy's pubic hair. On the headphones, she could hear the man moaning and the woman gulping as he unloaded down her throat.

Maddie made sure to make the videos on her thumb drive password-protected, and she changed the names so that they sounded like videos of physics simulations when she transferred them onto her home computer. She tried to look nonchalant as she made her way to the kitchen. She made herself a healthy lunch, including a pair of carrots. She washed both of them thoroughly and peeled them. No one saw her slide one of them into her pocket.

* * *

There were some very helpful tips on those videos, Maddie thought as she eased the thick end of the carrot down her throat. It had taken less than a week, and she could already drive the fat base of the carrot in and out of her throat without gagging at all. Well, she did have to ease it into her throat at first and let her uvula relax, but after that she could really fuck her throat with that vegetable.

She knew it was not as thick as her brother's delicious cock, but she felt confident that she would be able to enjoy every inch of him, starting that very night. Her drenched pussy spasmed as she thought about her brother's dick and drove the carrot in and out of her throat. She drove the orange phallus deep into her throat and held it there, quaking through her orgasm as she imagined her brother coming deep in her throat.

Afterward, she looked a little sadly at that poor carrot. Repeated use had caused it to swell and the outer layers were starting to dissolve. It didn't look good to eat anymore, and she knew that it would begin to spoil soon. She took it out to the kitchen and buried it in the trash. It had served its purpose.

It was Friday afternoon, and she changed into shorts and a t-shirt. Maddie had caught her brother looking at her body recently, and it excited her. Todd was so sweet. He looked guilty every time she caught him looking, but she always acted as if she hadn't noticed. She loved the way his cock swelled in his shorts during those moments. She looked at her reflection and could clearly see her perky nipples through that t-shirt. She smiled, knowing that Todd would certainly notice them.

Sure enough, as soon as Todd arrived home from school, he stood dumbstruck when Maddie popped up from the couch and bounced over to him for a hug. "Welcome home!" she murmured into his chest, holding him tight and relishing the feel of his erection throbbing against her belly button.

Todd looked down at her head for a moment before wrapping his free arm around her back. The transformation of his sister was still unbelievable to him. She was gorgeous! Now that she was no longer wearing her hair in that rigid bun, it was getting a little lighter. He had always thought her hair was very dark, but now it was light brown with lighter highlights. She no longer wore glasses, and her face was beautiful.

It wasn't just the glasses, though. She had always seemed so serious, reserved and unhappy. Now, she smiled all the time, and her dazzling smile was contagious. He smiled self-consciously as he held her for a precious minute. Finally, she released him and stood back.

"How was your day?" she asked.

He looked up thoughtfully, and so missed her furtive glance at his crotch. "School's been really weird this last week," he said. "It feels like some girls have been flirting with me, but I don't know why." He shook his head and looked back into Maddie's eyes.

"After Jasmine dumped me, she told a lot of girls that I was a real jerk. It was tough for a few days, and even some girls I had known for a while refused to talk to me. Now, all of a sudden, it's like they suddenly think I'm more attractive or something." He shook his head again. "Weird."

Maddie hugged him again. "Well, I think you're amazing," she said.

"Thanks," he murmured into her hair. He loved the smell of her shampooed hair.

He headed into his room after that brief hug, and Maddie watched him with a smile. Todd did look more attractive now. He looked happy, and carried himself with a comfortable confidence that was new. Maddie did not know that she was responsible for that change. Her nightly visits were carrying over into her brother's days as his satisfied libido made him somehow irresistible.

That night, Maddie shook through the most intense orgasms of her life with her brother's cock fucking her throat. She took him to the root and shuddered when she felt his hot cum pulsing through his shaft and right into her belly. She pulled back and nursed the last of it out of him. As always, she loved hearing him murmur "so good" as he filled her mouth.