This is a rewrite of an earlier version. Some comments suggested that part of the story sounded "rapish" because one of the characters was asleep, and I believe they were correct. It's never ok to have sex with someone who is asleep, my apologies. I think this version is better!
*****
For as long as he could remember, Mike's twin sister Ava had been an intense competitor. From ping pong to rock-paper-scissors, she never met a challenge she wouldn't bet on and go 110% to win it. Usually, she won. But that was before she decided to bet her brother on a friendly spanking contest.
The twins had spent a long day at the beach, hanging out with friends on one of their last days before heading off to college. An afternoon thunderstorm had rolled in and ended the day prematurely, and Mike and Ava had scrambled up to their family beach cottage to wait out the storm. Their parents were gone for the next several days, leaving the two of them to fend for themselves. After an hour of watching the storm, they gave up on the idea of more beach time, took showers and settled in for a battle over the backgammon table. As they played, they talked about their plans for the upcoming school year, and Mike surprised Ava by saying he might pledge a fraternity.
"A frat boy?" she laughed. "I sure didn't see that coming. I hope you have a tough ass."
"A tough ass, what are you talking about?" he replied.
"You know, for when they hit the pledges with paddles as part of the time-honored tradition of idiocy," she said.
Mike rolled his eyes. "They don't do that shit anymore, that's history."
"Oh yes they do," Ava replied. "I heard about a guy who couldn't sit for a week after pledging, he didn't take the time to toughen up his ass."
Mike looked at his sister carefully. Sometimes it was hard to tell when she was lying. "Well, my ass is already pretty tough," he said.
"Ha, that's a joke," she laughed. "I'll bet MY ass is tougher than yours," she said.
Without thinking, Mike jumped at the remark. "Care to make that an official bet?" he asked.
Ava blushed at the prospect. Over the years, the two siblings had developed an unwritten rule about any kind of challenge. When a challenge of any kind—from frisbee throwing to trivial pursuit—was accepted by the challenged party, it became an "official bet." The loser of any official bet had to pay the winner the lump sum of $1, though the real winnings were about bragging rights. Ava was always so competitive she never turned down a bet, and she wasn't going to start now.
"You're on," she said. Then she caught herself. "How are we going to determine who has the toughest ass?" she giggled.
Mike stroked his chin and thought about it for a moment. "We'll have a spanking contest, one slap per round, first to say 'uncle' loses," he said.
"Bring it on, little brother, your ass is going down in flames!" she yelled. She liked to refer to him as her "little brother," even though he was really only minutes younger.
"Just because your ass is older doesn't make it tougher," Mike countered. "Prepare to be ass-assinated."
"Okay then," she replied.
"Okay..." he said back.
There was an awkward pause as the idea of a spanking contest went from an idea to a reality.
"Ladies first," said Mike.
Ava briefly thought about laughing the whole thing off as a joke, but the challenge had been laid and she had accepted. "By ladies first, does that mean ladies spank first or get spanked first?"
Mike pondered the question and then grinned. "Ladies choice," he said.
"In that case, I choose to be the hitter in the first round, you'll probably quit after one hit anyway," she grinned.
Mike wasn't about to back down either. "Okay, where do you want me?" he asked.
Ava didn't waste any time. "Bend over and grab your ankles, bitch," she snarled.
Mike's eyebrows raised in a mixture of shock and horror.
"I'm getting you ready for pledge week," she explained.
Looking at her cautiously, Mike did as he was told, bending over to grab his ankles in the middle of the den. Ava walked over beside him, nervous at first but then deciding to go all in. "Prepare for the pain," she said.
She wound up and smacked him on the ass, but in her rush she neglected to notice that he had a wallet in his jeans pocket and her hand hit wallet instead of ass, which hurt her hand more than his ass. "Hey wait, that doesn't count," she hollered, ringing her hand.
"The hell it doesn't, the bet was one hit per round, if you're too dumb to hit ass that's your fault!" Mike was laughing so hard he nearly fell over. "Now its your turn to assume the position."
Ava knew she was about to lose the first round. She looked at her brother and suddenly realized that his muscular 6'2 build was likely to pack a significantly stiffer punch. Her eyes had a glimmer of fear in them as she leaned over and grabbed her ankles.
Mike strode up beside her, rubbing his hands together gleefully. When she bent over like this it really showed off her long, toned, athletic body, but all he was looking at was her ass, as he planned his assault. Just before he wound up for the hit, he saw the fear in his sister's eyes looking back up at him, and he backed off some, but it was still a solid full-on whack on the ass.
As Ava stood up, she quickly made an assessment that she hadn't made before. She was wearing a pair of cotton shorts, he had on jeans. She was going to have significantly less protection.
"This is totally unfair, we need to put on similar pants," she whined. "My shorts are way thinner than your jeans."
"Already begging for mercy," Mike smirked. "I didn't even hit you that hard. Okay, what do you propose that we put on—and by the way, I'm NOT going to wear a thong."
"We can definitely agree on that," she laughed. "How 'bout running shorts."
"Deal," he said, and the two of them went off to change clothes. Mike was back in a jiffy with a pair of loose fitting black shorts and a gray t-shirt. Ava took longer, and her outfit took Mike by surprise. She was wearing a pair of short pink shorts, form-fitting but still loose, and a sleeveless t shirt that was cut high so that it showed a good bit of her fit abdomen. It didn't take him long to see through the plan.
"I see what you're doing, you're trying to look all cute and sexy so I won't hit you so hard," he grinned. "It won't work."
She pouted and struck a sexy pose toward him. "Can't blame a girl for trying," she said. "Now bend over that couch, I want another piece of ass," she snarled.
Mike grinned and moved into place. He couldn't believe his sister was going a second round.
She moved into place beside him and rubbed her hands together. "I call this the fastball," she said, winding up her arm in a softball pitch motion. As her hand moved forward toward him, Mike remembered that as a softball pitcher, Ava had once thrown a no-hitter. She hit him so hard that he heard it before he felt it.
"Yowza," he yelled. "Damn girl, that hurt," he said.
She hooted and laughed. "I guess you give up then," she smiled.
Mike grinned and shook his head no. "I'm just getting started," he said.
Ava went from sassy to fearful in a heartbeat. "Oh shit," she said. "I need to get some courage."
She disappeared into the kitchen and came back out with a bottle of tequila and a shot glass. She downed a shot and found her defiant face again. "Where do you want me?" she asked.
"Hands on your knees," Mike said. "I call this the thunder."
Mike had noticed that the storm outside had picked back up, and the lightning and thunder was picking back up. Ava got into position and he stood beside her, standing where he could look at her but also see the lightning outside. He was waiting for a bolt of lightning to time his next hit.
As he waited for the lightning, he couldn't help but admire the shapely body in front of him. With her hands on her knees, her back arched, and her firm and shapely ass sticking out, he had to admit that his sister was looking quite sexy. He also realized that she was doing that on purpose, to get an edge.
Just then, a flash of lightning lit the sky, and he counted off a few seconds before slapping her ass just as the thunder boomed. At the same time his hand hit her ass, the electricity went out, and they were suddenly in the dark.
"Holy shit," she giggled. "Am I dead?"
"Not yet," he laughed. "That happens in round four."
They scrounged around and found some candles and soon had enough dim light to move around. Mike was thinking that the contest might be over, but he was wrong.
"Hands on the table, stud," Ava said. "I call this next shot my two handed backhand."
Mike, recalling that Ava was a two time county tennis champion, opted to have a shot of tequila himself before bending over the table. He watched Ava put her hands together and sway back and forth a few times, before deciding it might be best to close his eyes. Ava caught him strong and solid with the back of her left hand, pushed into place with her stronger right hand. Mike's eyes watered from the hit, he had to admit she could hit hard..for a girl. Funny thing was, almost the whole time his eyes were closed, he was visualizing his sister bending over and letting him slap her ass. Suddenly, he didn't want to stop playing this game.
"Okay, you're turn, hands on the table," he said.
Ava took the time to take another shot before moving into position. Mike walked around the table, taking his time, building the tension...and enjoying the view. He came up directly behind her, admiring her long, tan legs, and smiled demonically at her as she looked at him in the wall mirror.
"I call this the little drummer boy," he said. Before she could protest, he gave her a quick three slaps with each hand, three on the right cheek and three on the left. The slaps weren't very hard, so Ava was so relieved she didn't protest the fact that he had hit her more than once.
"Very nice," she smiled. "I always knew you had musical talent."
Mike took another shot of tequila and bent over the arm of the couch. "Okay sister, what do you have for me this time," he said.
"I call this cat scratch fever," she grinned. Mike was trying to imagine what that might end up being when he felt Ava's hand pop down firmly on his ass. Her hand stayed on his ass for a split second, and then he felt her hand lift up and her fingernails dig lightly in and then briefly give a playful scratch on his ass. It was not, in any way, painful, and Mike realized that Ava was returning the favor he had given her by not hitting her that hard.
"Whoohoo, we should make some kinda rule about drawing blood," Mike said.
