"Oh fuck, that feels good," Jennie moaned as Joe's hands slid down her back.
"Is that getting it?" Joe asked.
"Maybe. I don't know. I can still feel it in my middle back."
Joe and Jennie had been swimming on this hot summer day for the last hour. They both had the day off from their respective summer jobs, and they needed the break. Joe had been rushing from the convenience store to baseball practice every day, and Jennie had worked a whole week without a day off at the video store. She usually didn't mind so much, as she would need the money for books in the fall. The campus stores weren't cheap, and the used bookstores weren't much better. Joe was trying to save up money for the start of his freshman year at college next year, but figured most of it was going to be spent on the prom this year. He was desperately trying to get into Wendy Yost's jeans, but so far had no luck. He figured a nice night of wining and dining might lead to some sixty-nining.
Their parents were out of town, gone for a visit to their Aunt Andrea's place in Chicago. They both decided at breakfast that morning to do nothing but laze around the house all day, swim now and then, and watch Iron Chef together later that night.
However, while swimming, Jennie got a tight knot in her back. It was bad enough that Joe helped her out of the pool, for fear that his sister would fall over. He laid her down on a beach towel, hot from the July sun, and started to knead at her back after she asked him to help get it out. Joe's strong catcher's hands soon rubbed rough on Jennie's soft back though, and she nearly crawled away from him in pain.
"Shit, Joe! You're givin' me an Indian burn!"
"Sorry!" Joe blurted. "I didn't...Hand me that oil."
"Good idea," Jennie agreed, and handed Joe the bottle of tanning oil.
The oil was hot in Joe's hands and Jennie turned her head to her left and let out a deep breath as her brother's hands, all slippery and warm, slid down her strong back.
"Aaaaah!" She winced, baring her teeth.
"Is that it?" Joe asked, pressing deeper into the knot just under her bikini strap.
"Yes. Fuck, that hurts."
"You want me to stop?"
"No, it's a good hurt." Jennie chuckled. "Here." She folded her arms behind her back and untied her dark green bikini top, revealing the final inch of her spine to Joe's slippery hands. Joe sunk his thumbs into her hard muscles, making little fishhooks with them and drawing the tension further away from her spine.
That's when he noticed the throbbing under his swim trunks. They were still damp, but quickly drying in the July heat. His cock was growing by the second as he straddled over his sisters thighs and worked his fingers into her back. The base of his cock was fitting quite nicely between her ass cheeks, he noticed. He wondered what she was thinking. He wondered what he was doing! His heart was racing and the sweat on his forehead seemed to be coming out of hundreds of little faucets behind his hairline. She had to notice. How could she not?
His hands moved to her lower back, brushing along the top of his bikini bottoms and barely brushing her hips. He looked over his sister's ass for a good long while as he pushed his thumbs into her sacrum. His eyes roamed down her thighs and then back up her ribs, trying to catch a peek at her breasts.
"You wanna try and pop my back?" Jennie asked.
"Yeah, sure," Joe squeaked.
He cupped his hands together, leaving the edges of them on either side of his sister's spine. He thrust forward with his hips, shoving his hands down and forward. Jennie's upper back made a deep popping sound, and she let out a sigh. Joe's hands dropped a bit more, and again Jennie's back let out a blissful crunch. Joe tried the lower back, but nothing went back into place. He tried again, shoving his hips forward, and digging his cock into the cleft of his sister's ass. He tried again, letting out a loud grunt. Jennie's back arched up a bit as he pressed into her.
"Wow, Joe, are you trying to fuck my ass or what?" She laughed.
"No!" Joe laughed nervously. "I was just trying to get your lower back in, that's all."
"Well, you can rub my ass, Joe, but don't fuck it! Geez!" She laid her head back down on the towel.
"You want me to rub your ass?" Joe asked in disbelief.
"Yeah, it's sore too!"
Joe, his hands shaking, pulled his sister's bottoms down off her. Her whole tanned, naked, nineteen year-old body laid before him. He was trembling. Her legs were long, her thighs were strong, her ass was firm. He squeezed oil over her cheeks in little dribbles. Jennie moaned happily, and Joe squeezed his sister's ass in both hands. His fingers kneaded into her muscles, and her body writhed slightly. Joe noticed her smiling. Was she getting off on this? His cock felt like it could burst at any second. His thumbs dragged along the backs of her thighs, creeping inside just a bit. Jennie spread her legs just a bit, and Joe's thumbs brushed over her lips.
Jennie gasped. Joe bit his lip.
"Oh, fuck, Jennie. What are we doin'?"
"I don't know, Joe. Just touch me." She raised her hips a bit, and reached down under her belly to spread her lips a little more. It was the most erotic thing Joe had ever seen. His sister was splayed out on the towel before him, one of her feet dangling in the pool, and her wet cunt open for him.
He brushed over her clit with his fingers, and she cried out sharply, nearly scaring Joe. He let out a deep breath and twisted one finger into his sister's cunt. She moaned and pushed backwards, sending Joe's finger deeper. He used his middle finger to stroke her clit, and she gripped the towel. Her mouth opened, but she only made little, halted cries as she came. Joe groaned as she clamped onto his finger and wiggled under the hot sun. She bit her lip as her hips moved in languid circles. Joe pulled his soaked hand away as his breathing was speeding up out of control.
"Fuck! I'm gonna cum!" He realized.
"Let me see, let me see!" Jennie spun around surprisingly fast, yanking down Joe's trunks as soon as she faced them. Joe's rigid cock was spurting hot, sticky cum in a high arc. Jennie cheered and squeezed the base of Joe's cock. Joe let out an "Oh!" that echoed into the neighbor's yard. Joe looked around in a panic, and then remembered the seven foot security wall around the pool. His cum splashed onto his sister's shoulder as she moved away from it landing in her hair. Joe nearly collapsed atop her.
"Shit!" Joe yelled as he shuddered. "I never came so hard in my life."
"What? All two times you've cum, not counting all the jack-offs in your bedroom?"
"Oh, fuck you!" Joe snarled and pushed her into the pool. She came back up immediately at the poolside in front of him. He kneeled before her, his hands on his hips and laughing a macho guffaw. She looked at him with a glance of teasing anger.
"Why don't you join me?" She beckoned with her middle finger.
"Oh no!" Joe held up his hands. "You'd give me a super wedgie with my trunks or something."
"Maybe." Jennie smiled, then pushed herself up from the water. She leaned forward just right to wrap her lips and tongue around the head of Joe's softening cock for just a moment.
"Maybe not." She grinned, and slipped back into the water, leaving Joe with a suddenly cramped stomach and an urge to get his trunks completely off.