Liam always loved hanging out with his little sister. Going to the arcade, watching movies at the theater, or just riding their bikes around town and going to the playground. He and Tiffany were never far apart. They even discovered porn together at a young age when Liam correctly guessed the password on the parental controls of their home computer. Their parents never seemed to pay much attention to them, so they were never caught. It wasn't certain what kinds of feelings those adult images and videos made them feel, but it stirred something in the both of them.

Their most favorite thing to do was going to the water park during summer. Tiffany would practically beg her big brother to go almost every day of the summertime. The siblings would spend all day in the pools and water slides before walking home together. Life was good and they enjoyed the innocence of youth as an inseperable pair.

When Tiffany turned nine and Liam was ten, the water park opened once again during an especially hot weekend. Tiffany popped into Liam's room without permission (like usual) and spied him in bed, "Hey, stupid!"

"Hey, dummy," Liam tried to roll out of his blankets.

"Mom and dad are at work again and the pools just opened! Come on, we gotta go!"

He rubbed his eyes and stretched, with a bedsheet barely covering the lower half of his naked body, "Are you sure they open up today, Tiff? I thought it was next weekend..."

"Yes, yes, yes!" Tiffany was in no mood for his teasing and practically bounced around. "I double checked! They're open right now! Come on, let's go, please! Puh-leeeease!"

It was impossible for Liam to say no to her, especially when she really wanted something. He finally slumped out of bed and went to his closet. Being naked around each other was natural at this point, but Tiffany still caught a good eyeful before leaving his room. Things always felt comfortable between them, but lately Tiffany was started to feel confusing urges and had taken to looking up more of those naughty videos when she was by herself. She found herself wanting to try the mouth thing she watched so often, remembering the look on the man's face and how good it seemed to feel. Tiffany would do anything for her big brother and wanted to make him feel good too. After all, he did so much for her.

They met by the front door in their swimming suits and began the ten minute walk to the water park. The sun beat down hard and Liam wondered if it was some kind of record breaking heat. Tiffany skipped along beside him, slowly putting a plan together in her mind and working up the courage to act on it. 

"Liam?"

"Yeah, Tiff?"

"Do you have a girlfriend?"

He seemed surprised by the question, then laughed, "Well, no. I don't have a girlfriend. That's a funny question."

"Oh... why not?"

"Well, umm..." Liam gave it a little thought. "I guess I just haven't looked for a girlfriend. I don't need one, really. I have you to play with!"

Tiffany was satisfied with his answer and beamed. After a few moments, she felt like being mischievious and yelled, "Hey! There's a bee on your butt!" Before her brother could react, she slapped his backside as hard as she could and started to run away.

"Ow! You little shit, get back here!"

When they finally arrived, Liam dug out some money he'd been saving and payed the attendant. Allowance well spent. The man recognized them from last year and waved them through with a smile. Children didn't need to be with an adult as long as they stayed in the kiddy section of the park, so they passed through the locker rooms and entered into the pools.

Looking around the main area, they were hit with the sounds of splashing and smell of chlorine and a familiar childish excitement took over. It was opening weekend, but there were maybe three other people swimming so far. Which meant they had the place practically to themselves to go riding the slides and messing around in the shallow end. Tiffany tried to do handstands in the water, so Liam playfully tackled her. Their bodies rubbed up against each other as they wrestled around and Liam accidentally groped her petite rear in the scuffle. He looked down to see what was so soft and blushed when he noticed where his hand was, pulling away out of embarasment.

"Oh! Uh, sorry! I wasn't grabbing for your butt, heh," Liam blushed. "I thought that's where your leg was..."

She splashed him and teased, "You don't have to be sorry, stupid."

After a few more minutes, Tiffany got an idea and climbed out of the pool, walking to the girls showers and coming back out a few moments later and waving for Liam to come over. He knew that look on her face. She was up to something. Still, he pulled himself out from the water and casually walked over. "What are you doing over here?"

"The showers are empty, I want you to come in with me."

"Tiff, this is the girl's showers... and I'm not ready to leave yet."

"Just come on, I want to show you something!" she gave him a light punch on the arm and turned to go back inside, knowing he'd follow. Liam didn't want to argue, so he made sure nobody was watching and followed after her.

He couldn't help staring at her backside on the way to the far end where the lockers were. The bottoms of her swimsuit were clinging to her ass, sliding into the crack and exposing her cheeks at the sides. He suddenly found himself fighting every urge in his body to not pitch a tent in his trunks. The thrill of being inside the girl's showers was only making that more difficult. It's not that he was a perv or anything, but the circumstances were quickly working against his better judgement. Besides, there was no harm in just looking. Right? Tiffany had stopped and started to ask him something, or at least he thought she did, because he'd become lost in his own thoughts and hadn't been paying attention. 

Suddenly, they heard some older girls chatting loudly and entering the showers.

Liam snapped out of his trance and both siblings start to panic. Liam wasn't supossed to be in here. They were back far enough near the lockers that they weren't seen right away and could get into one of the showers. Liam pulled the curtain closed before they were noticed. Tiffany turned the water on to mask any sounds they made and Liam's heart started racing as he sat down on a seat jutting out from the tile wall. It was a big enough shower that the seat wasn't under the water flow, so he took a moment to calm down and listen. The voices were getting closer.

"Tiff, why did you bring me in here?! I'll get in some serious trouble if they find me snooping around the girl's showers... They might kick me out forever, or worse!" he tried to keep his voice down, so the shower could mask the noise. He could hear the wet slapping of their feet on the floor as the girls approached the lockers.

"You're not afraid they'll catch us, are you?" Tiffany didn't seem nervous anymore and resorted to teasing him again. "Don't be such a scaredy-cat."

"You're such a little shit," he snapped, more stressed than angry.

Tiffany had a good feeling now was the time to be bold. When he glanced over to his sister, she was putting one finger to her lips as a signal to keep quiet. She looked so serious. With the image of her ass still fresh in Liam's mind, and the adrenaline from their situation spiking his heartrate, his swimming trunks became uncomfortable. He glanced down to see he'd sprung a full erection that was creating a very noticable buldge. He clumsily shifted his body to hide it, but not fast enough. Tiffany was already reaching down and placed a gentle hand on his cock through the wet fabric. 

"Tiff! What the hell are you-" Liam started, then stopped to keep himself quiet again. His first thought was that his sister would make fun of him for getting hard. His flustered mind not understanding the dirty thoughts she secretly had for him. Instead, she sat down on the tile floor in front of her big brother and pulled the trunks down his legs, then looked up at his face in a silent question of 'do you want me to keep going?' Her eyes were so innocent and charming in that moment. He could hear the other girls outside getting closer to the shower, gossiping about who-knows-what. He hesitated only for a moment, then nodded and allowed his muscles to relax just a bit.

Tiffany positioned herself so Liam's legs were on either side of her shoulders. She began by resting his hard cock on her face, its length resting over her nose as she closed her eyes and seemed to be enjoying the strong scent of her brother's member. He stared down at the sight of her and found his mind filling up with a lustful haze. "I'm your big brother, this is... you don't have to-" She stuck her tongue out and licked the underside of his boyhood, working slowly from the base until reaching the tip. He shivered and decided not to speak again.

When Tiffany took the head of his cock in her mouth, she gave it a few quick swirls with her tongue and savored the taste. As he was halfway into her mouth and she became focused on her task, the girls outside were walking right outside. Then they stopped to keep talking, with just a cheap curtain between them and the siblings. Only one wrong move away from getting caught.

"-and that asshole thought I wouldn't get mad. It's like he never thinks of anyone but himself."

"You can do better, girl. Take a break and see how he likes it." The two girls sounded like they were in high school, absentmindedly chattering and invested in their conversation.

As Liam's pulse raced faster, he placed his hands up to Tiffany's head and slid his fingers through her hair. His first instinct was that he could push her away quickly if he needed to, in case the girls outside opened the curtain and saw them. Allowing Tiffany to continue was such a risk, but he'd lost himself in the feeling of her mouth exploring every inch of his cock. He whispered just above the sound of the water, "Suck a little harder, sis... move your mouth up and down." She eagerly obeyed. He never thought she could be capable of something like this, but this young girl was bobbing up and down on him like a natural, sliding her tongue with each motion to feel around his entire length. She gagged a few times when going too deep, but the sound of running water kept them hidden.

Finally, the girls outside continued walking and seemed to leave. Liam let out a sigh of relief mixed with pleasure and gripped Tiffany's hair tighter, helping to guide her movements with more intensity. She didn't struggle, all too happy to please her big brother. Liam found himself thrusting up into her greedy mouth and moaning loudly. Without warning, he pushed her head all the way down to the base of his swollen cock and unloaded down her throat. Tiffany wriggled beneath him, moving back and forth on his length and increasing the intensity of his orgasm by simply trying to pull away. She had no choice but to start swallowing every spurt of warm cum being pumped into her throat. She gulped it down until he finally stopped cumming, eventually realizing that Tiffany had to breathe and let go so she could pull her head back and catch some air. Tiffany coughed a couple times, but then went back to suckle on his cock, licking him clean like a treat.

"Where did you learn this?" Liam stammered. "You're only nine."

She looked insulted, "You're only ten!"

He couldn't argue with that. In fact, he found it kind of funny. It seems they'd both been watching more of those naughty adult videos without telling anyone. "Hey... I want to make you feel good, too." It was only fair. After all, they had already come this far. 

Liam poked his head out to confirm the room was now absent of any more poeple, then turned off the shower facet. "Okay listen... lay down on the tile, on your back."

She complied without question, which was rare for the little trouble-maker, and Liam delighted in stripping off her skimpy swimsuit. The top was tossed aside first, exposing her undeveloped chest. Followed by the thin strip of cloth that covered her virgin slit. Laying naked on the wet floor, exposed and wondering what would happen next, Tiffany looked more beautiful to her brother than ever before.

“Now, spread your legs and relax,” Liam placed his hands on her knees and gently pushing them apart to get between them. He wasn't even sure if she was able to have an orgasm at this age, but even if not, he wanted to taste her. He leaned down until she could feel his breath on her most private place. Liam gave a long, firm lick over her tiny mound, forcing a gasp from his precious sister. A small pair of hands came to rest on the sides of his head as he worked his tongue over her, gradually picking up the pace. Suckling from time to time around her clit to earn a delighted moan. 

“Whoa... that feels funny,” Her words made him smile and move his tongue faster. Liam pressed two fingers against her entrance, feeling resistance from the tight hole. She seemed just wet enough to continue, so he slowly worked his fingers from side to side, pushing them firmly into her. Tiffany's hands clenched his head as he drove his fingers deeper, wiggling them around inside and enjoying the noises she made. “Your moans are so cute, Tiff. I hope I'm making you feel good.” He licked his lips and dragged his tongue across her tiny clit, working his fingers with more vigor.

Before long, Tiffany was crying out and holding her brother firmly against her crotch. “I feel weird. Something's happening,” His fingers worked faster, invading her young pussy. He stopping licking briefly to comfort her.

“I think you're going to cum. Let it happen, just enjoy the feeling,” Liam removed his fingers and slipped his tongue inside, probing around as deep as possible. His fingers moved up to rub and lightly tease her clit. Swirling around and around. The stimulation finally pushed her young body over the edge. Tiffany's back arched, her legs shook, and she came hard against her brother's mouth. Only a labored squeek left her mouth as she experienced the first orgasm of her life. Liam noticed she wasn't producing much fluid because of her undeveloped body, but licked hungrily anyway until she was finally spent.

Liam cleaned her tender slit with his tongue and enjoyed the taste until she lightly pushed his head away. Tiffany felt dizzy and turned to face her big brother. "Hey, Liam?"

"Yeah?"

"I love you."

Liam smiled and kissed her forehead, "I love you too, sis."

A man's voice called into the showers from outside the door, "Hey! Everything okay in here? I thought I heard noises!"

The siblings were brought back to reality and began pulling their swimsuits back on in a hurry. Tiffany poked her head out from the curtain and shouted back, "Yeah, I'm okay! Just getting ready to come out! Umm... Don't come in here!"

Liam grabbed her shoulders, "Don't tell him not to come in here, that sounds suspicious! It'll make him want to come in here!"

"No it won't, this is the girl's showers! Just shut up."

"You shut up!"

After they heard the man walk away, Liam and Tiffany casually slipped out from the showers and walked fast to the park exit. They were hoping no one had noticed anything suspicious, but didn't stop to check. Only slowing down once they were halfway home. Then they looked at each other and burst into laughter.

"I can't believe that just happened... Can you imagine if we got caught?" Liam felt a sense of relief. "Actually, what I can't believe is that you started all that. Have you been looking at those dirty videos again?"

"Well... yeah," she admitted. "But I just wanted to do something nice for you. Besides, you liked it!"

Liam nodded, "I think you did, too. You know what... We should try more things together. Things like that. I mean, if you want to."

Tiffany grinned, then reeled back and slapped him hard on the ass. As Liam yelped in pain, she was already running away, "Race you home!"

"Not so fast you little shit!" He chased after her, his eyes drifting down to her backside again.