Accidental Test Subject (Closed for The_J0k3R)

“I’m not…” Tommy said, clinging to her as much as she was clinging to him. He couldn’t deny that his loins were filling, rapidly, at the feel of her wet, full breasts pushed into his chest. His cock throbbed a bit when it rubbed against her belly, and there was nothing he could do to hide it or shield her from it.

He kind of wanted her to feel it. He could tell that he was still feeling some lingering effects from the potent cookies, and was curious… for scientific reasons, of course… if she was experiencing the same thing. He had no doubt that she would be.

He closed his eyes, dirty thoughts running rampant through his mind as the blood focused harder and harder in his crotch...
 
Sadie was noticing, and trying to fight acknowledging it. "You're not?" She asked confused. Her breath was becoming heavier, but she tried to control it. Her nipples were becoming harder and rubbed against her brothers chest. She started shuddering. Oh no! she thought. It felt like before when she was in her brother's bed. Not as strong as before, at least not yet.

Sadie tried to pull away, but as soon as she took a step back she started to slip. To keep from falling she clutched onto Tommy tighter. Her body had jostled against his, feeling his hard member rub against her caused her to moan right in his ear. She needed to get out of there before she did something she'd regret... again.

"I... I think I need..." To leave. She needed to leave. She pulled her head back... but then only to turn to him and press her mouth against his.
 
Tommy moaned as she grabbed onto him, her body rubbing against his growing erection. His hands clutched her tighter, and when she said she needed… him… he responded in kind to her kiss, his arms pulling her in firmly, pressing her full, firm breasts to his chest as their tongues rolled over each other.

It was like a decade of pent-up lust was being released all at once, all over again. The kiss quickly grew heated and passionate as they stood together, naked in the hot shower. Their hands grasped at each other to pull each other against them.

A pang of guilt hit Tommy, even as his hand slipped down to cup her supple round buttock. Sadie was only doing this because of the effects of the drug he had fed her. Perhaps, that was the only reason he was doing it as well. It wasn’t natural.

But as his cock throbbed against her, and she moaned into his mouth, it sure felt as natural as could be…
 
Sadie moaned against her brother's lips. All sane thoughts were slowly slipping away. Suddenly she couldn't get enough of his body against her, or his kisses. She needed more.

Sadie pulled Tommy closer to her. Between kisses she would take deep breaths as her body rubbed against her brothers. When he grabbed her ass she kissed him harder, more desperately. Her leg started to raise up until her thigh was at his hip.

"Tommy..." She moaned, helpless against the desires of her body. She pulled her mouth away from his only to find his neck. Her lips caressed his skin, gently nipping.
 
Tommy felt her lips on his neck, and it was like a fire being lit upon his skin. His fingers dug into her flesh, and as she raised her leg, opening herself to him, he could feel that delirious wet heat rub against his now-throbbing member.

"Fuck," he groaned, his cock twitching between her thighs, his shaft rubbing along her dripping slit.

He pushed her up against the cold tile wall, and pressed himself against her, his desire growing to uncontrollable heights. He hooked an arm under her knee, raising her leg up to expose her pussy to his hungry, pulsating dick. With his other hand he grasped himself at the base, and rubbed the thick head along her dripping, ravenous slit.

"Do you want this again?" he growled in her ear...
 
Sadie gasped and held onto Tommy as he pushed her against the shower wall and lifted her leg up higher. She was completely open to him. She moaned in his ear as she felt him rubbing her slit with purpose. Her body was begging for him. There was a small part of her in the back of her mind trying to remind her that this was her brother, that they needed to stop before they ended up regretting this...

But every touch and kiss between them was maddening, but it was also quieting that nagging voice.

"Yes," She breathed out softly. "Yes, I want it."

Sadie's hips bucked, emphasizing how much her body needed. She needed her big brother to make her forget how wrong this was. She needed him to make her feel good.

"Please... put it inside me." Sadie bit her bottom lip as she moaned once more.
 
Tommy's cock throbbed immediately, rising to full mast, when she told him to put it in her, and with a single thrust of his hips, he did exactly that. He groaned in delirious pleasure as he felt her sweet, tight folds wrap around his stiffened member. His hands gripped her tight, and he held her against the wall, savoring the feeling of her pussy contracting around his thick cockhead.

How could he possibly resist? He grunted in ecstasy as his hips seemed to take over. His hands pulled her hips towards him and he drove upwards into her, taking her fully in a long, slow, firm stroke that was unrelenting as he felt her cunt gloriously open up for him inch by inch.

His eyes locked with hers. "Fuck..." he growled, his cock throbbing again, so terribly deep inside her...
 
Sadie gasped and groaned softly as she felt her brother's thick cock push into her tight slit. It hurt for a moment, still tender from when he first took her innocence. He felt so thick! Once the discomfort passed he was driving his cock deeply into her as the water rained down on them.

As the two were in the shower, unknown to them their parents had come home from their trip, only for the day (it had been for work). They brought in their luggage and their mother climbed up the stairs to check in on their daughter as Tommy was supposed to be at a class party. Coming to her daughter's room she noticed that she was not there, but she could hear the shower. As she came closer to the door she heard a strange sound. She knocked.

"Sadie, darling? Are you alright?"

"Mom?" Sadie gasped as she held onto Tommy tighter. Her legs were wrapped around his waist as he was stuffed deeply inside of her. Sadie's heart was pounding! She was sure that the door was unlocked. Would she come in? Would she see that she wasn't alone in the shower?

The thought of getting caught like this both scared her and gave her body a strange rush. Her pussy squeezed around Tommy's cock, unwilling to let him go until they both were satisfied.

"Your father and I are home for tonight but then we are leaving again in the morning. When your brother gets home we will have dinner together, alright?" Their mother's voice sounded soft and cheerful, tired from her travels but happy to be home.

"o-ok!" Sadie squeaked out, biting Tommy's shoulder though not enough to break skin as she tried to keep herself from moaning. God, she was getting fucked in the shower by her brother while her mother was talking to her through the door.
 
Tommy's heart skipped a beat when he heard the knock on the door and their mother's voice ringing out. His eyes grew wide as he looked at his sister and listened, doing his best not to moan and grunt. He held Sadie firmly against the wall, his cock buried so deep within her. He could feel it throbbing, spasming hard inside her cunt.

He winced at her teeth on his shoulder, biting him, and he immediately responded in kind, sinking his own teeth into Sadie's shoulder for the moment, and thrusting up into her roughly.

That's when he had a most terrifying thought. The cookies. Mom was known to have a sweet tooth, and a stray plate of home made cookies would be irresistible to her if she came across them in his room.

Dear God in heaven, his room! He was sure it still stunk of sex and fucking and cum. Would she know? He thrust hard up into his sister again, and again. He had to finish and get to those cookies!
 
"I could make something or-" Their mother stopped when she heard Sadie let out a yelp from her brother thrusting hard into her. She hadn't been expecting it. Sadie was trying to pant as quietly as she could, trying to keep herself from going over the edge. Her body was shaking from how close she was.

"What happened? What's wrong?" Sadie held onto Tommy tighter as she heard her mother turn the door knob and opened the door, but only about on inch so she could hear better.

"Nothing!" She said quickly, "I just slipped and almost fell."

Oh god, their mother was on the other side of the door, it was open now. All the woman had to do was open it and step in. Thankfully she didn't, but the thought of it happening, of getting caught and someone seeing her like this was enough to push her over the edge. It took everything she had but Sadie covered her mouth with her hand tightly managed not to make a sound as her body shuddered and her pussy convulsed around her brother's shaft.

The next thing Sadie remembered hearing was the bathroom door closing. She missed her mother scolding her and telling her to be more careful before closing the door to let her finish her shower.
 
Tommy stifled a groan, even after he heard the door shut, as Sadie's pussy clamped down hard around his cock, and the way her body convulsed on him as he held her impaled on his cock, he knew she was cumming, and hard, from almost being caught.

It was enough to send him over the edge as well! He felt that familiar, incredibly intense release, his cock swelling and throbbing, his balls roiling and clenching, and he thrust hard up into her and let his cock drench her insides with even more of his copious seed...

Fuck!!! He thought. The cookies! He couldn't let Mom get ahold of them! But how to get there?
 
Sadie was still holding onto Tommy tightly, both with her arms and her twitching slit. Another shudder ran through her as he once again filled her with cum. God... what was this, the fifth time? She needed to stop letting her brother cum side her... SHE NEEDED TO STOP FUCKING HIM. There was a part of her that got excited at the idea of getting pregnant by him.

As she started to let him go, Sadie could hear movement from her brother's room, followed by their mother yelling. "OH MY GOD, WHAT THE HELL HAPPENED IN HERE?!"

Sadie's eyes widened as she could hear their dad come up stairs to see what the commotion was about.

"That's it, John. You tell your son 'No more experiments at home!'" It seemed like mom was unaware of what the actual mess was in the room... Dad seemed a bit more wiser.

"I don't think this was an experiment, Helen... but I will definitely talk to him about cleaning up after himself."

SHIT! Did she leave her clothing in there? She had been in such a rush to get to the shower she couldn't remember. Their parents were looking at the evidence of what they had done!

"And he knows how I feel about leaving food in their room!" Sadie was still unaware of the effects the cookies had. She waited until she was sure their parents went back down stairs.

Turning off the shower and opening the curtain she let out a sigh of relief. On the bathroom floor was her school uniform, or what was left of it. For now their parents had no idea that she had 'helped' Tommy in creating the mess in his room.
 
Tommy gulped as they listened to their parents talk about his disaster of a room. His heart skipped a beat at the word "experiments." Did Mom know? She couldn't! The special experiments were all known only to him! Fuck. Did she take the cookies? That could be bad.

That could be very, very bad.

Tommy dried off quickly once they were out of the shower, and wrapped the towel around his waist before scurrying over to his own room. It was quite the mess. He breathed a sigh of relief when he saw the cookies were still there. Counting them would be useless, as he had no real clue just how many they had eaten the night before.

His thoughts wandered back to his sister. He was sorely tempted to give her more. Just to see what happened. That was probably a bad idea with mom and dad home, though, right? He was tempted to eat one himself, just because it felt so damn good to have such a hard-on and to be able to cum so much...

He set the cookie down and pulled on a pair of gym shorts and a tee shirt.
 
Sadie dried as well and went to her own room. One good change that came from this was that now her bottom filled out her jeans better. She had the curves she always wanted. When it came to finding a top... that was a bit of a challenge.

None of her bras fit anymore. Sadie went from a basic B to... what? Ds? They were so heavy. Now she knew why her bustier friends complained about them so much. How was she going to explain her new figure to her parents? She didn't have anything to bind them down.

Sighing in defeat she just found an over-sized T-shirt... well it use to be over-sized, now it fit perfectly. The fabric hugged her breasts tightly. Maybe she should stay in her room for the time being? Just until she could figure out what was happening to her.

Meanwhile, down stairs Helen was chewing on one of the cookies her son made. She should have just taken the whole plate down but she knew that she couldn't be trusted with them in front of her. What had happened in that room?! There was stuff all over the place. If he thought she was cleaning that up, he had another thing coming.
 
Tommy went about cleaning up his room. He could take a hint, after all, and it kept him from having to deal with his parents. All the bedding needed washed. Badly. Good god in heaven, how was there so much cum?

He picked up the comforter off the floor, and found, underneath it, his sister Sadie's plain white panties from the night before. The ones she had cum in. They were still wet with her juices. His cock twitched at the find. He looked back at his door; it was shut. There was no lock on it.

He raised it up to his face and took a sniff. His nostrils filled with her orgasmic scent, and it brought back all the memories of the night before in a flood if arousal. His eyes went back to the cookies. Maybe just a nibble... he thought, grabbing a cookie and breaking off a bite, chewing and swallowing it down.

He dropped his shorts and sat down on the bed, wrapped his sister's wet panties around his growing cock, and started stroking it...
 
Sadie started putting her clothing in her laundry hamper. She had her shirt, skirt, socks, her mangled bra went into the trash... But where were her panties? She started searching her room. They weren't where she tossed her clothing earlier. Checking the bathroom, she was sure it would have been in there! Again there was nothing.

They must have still been in her brother's room. Sadie hesitated. She was unsure if she should go in there so soon and with their parents home...

'It's not like he is going to attack me and try to fuck me while mom and dad are home,' She reasoned with herself. She first knocked on the door to his room.

"Tommy? You in there?"

It was then a loud moan could be heard from down stairs. Two of them to be exact. What was going on? Sadie twisted the door knob and came in.

"Tommy, I need my- WHAT ARE YOU DOING?!" She froze in her tracks, her eyes glued to her panties wrapped around his cock.
 
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