After their little car wash/water fight, the girls went out to the backyard, where a pool the size of a sports stadium awaited them. They knew they'd eventually use it but Rias pointed out something else. A slip and slide. About 70 feet long, that went into the pool.
"The rules are..." Rias explained. "We each take turns going down the slip and slide and into the pool while posing sexily. After a few turns, we'll both go down it at the same time and pose together. We judge each other on a scale of 1 to 10 based in style, sexiness, flexibility and how we emerge from underneath the water. Whoever gets the lower score has to eat the winner out underwater."
"Well, good thing we're not humans." Akeno commented. "They're lucky if they can last a minute underwater but we can hold our breath for hours."
"Indeed." Rias said. "And I installed water proof cameras inside of the pool and my servants make sure the water is nice, clean and clear so our Issei can enjoy the show to the best possible extent."
"You really thought of everything, babe." Akeno complimented.
"Nothing's too good for our man." Rias said with a smile. "Now, who's up first?"
"You dominated me during that car wash, so I only think it's fair you go first." Akeno said.
"Thanks, babe." Rias said and pecked Akeno on the lips.
Rias turned the nozzle and the water on the slip and slide started to run. As the slide got nice and wet, Rias stepped back and then got a running start towards the slide. She dove into the slide, crossing her legs, stretching her arms out with her hands giving the meditation sign and stretched her neck up while looking into the sky with her eyes closed. A Buddhist pose and a very refined one that showed off her lovely flower. She maintained this pose until she slid off into the pool, which was apparently quite deep as she emerged six seconds later, flipping her wet, red hair slow motion style. She opened her eyes and looked at Akeno.
"How was that?" Rias asked.
"Not bad. 7 out of 10. Very elegant and classy but could've been more sensual." Akeno said.
"Well, let's see you give it a shot, slut." Rias teased as she got out of the pool and shook the water out of her hair.
"Maybe I will, skank." Akeno teased back.
Akeno got in front of the slide and like her rival, she took a few steps back before running towards it and diving onto it backwards and sliding on her back, spread eagle. She grabbed her feet and pulled on them, giving a very clear view of her pussy. She appeared to be mimicking a missionary sex position. She made faces as she closed her eyes to add to the illusion that she was getting fucked and then finally fell into the pool. Five seconds later, she came up, her entire form dripping as instead of flipping her hair mermaid style like Rias did, she shook it around left to right and it flew all over the place, splashing even Rias.
"Impressive. 8 out of 10. Slutty, as befitting of your character, the faces were a nice touch and it shows off your flexibility quite nicely but missionary? Girl, you know you can do better than that." Rias said.
"Just warming up, sweetie." Akeno excused. "Your turn."
Akeno got out of the pool, squeezing the water from her hair as Rias took position at the slide. She stepped back and practically swan dove into the slide, before putting her ass up into the air, wrapping her hands around the back of her knees and shaking her tight ass as if to say "Come and get it, Issei". She pulled one arm back to her face and put her index finger and thumb into a gun pose and winked like an anime girl. You could almost her the sparkle sound effect that would make the look complete. She posed doggy style until she feel into the pool and as she emerged, this time, she flipped her hair in Akeno's direction, splashing her as payback for earlier. Akeno giggled as she used her hands to shield herself from the splashing.
"Doggy style, eh? 9 out of ten. The winking and finger gun was a great touch and it takes a true slut to wiggle her ass in such a provocative way but it could've been a bit more elegant." Akeno said.
Rias got out of the pool again, this time letting her hair drip as she realized it was pointless because it would just get wet again. Akeno didn't waste any time and dove into the slide. She sat up and spread her legs while hopping slightly. She took one hand and balled her hair up into her fist behind her head in a mimic of the reverse cowgirl position. A favorite of Issei's. This time, she made an effort to actually moan out loud to add to the illusion. She fell into the pool and as she emerged, she instead laid her back in the water and breathed heavily as if she really did just get fucked. She even managed to make herself blush.
"Wow. 10 out of 10. Talk about commitment. The hair pulling, the moaning and the heavy breathing at the end? Perfect." Rias said. "Now, how do I top that?"
Akeno got out and like Rias, didn't even bother wringing out her hair this time. Rias was actually perplexed as to what she was going to do next and then she grinned as it hit her. She knew those yoga classes would come in handy one day and it wasn't just an excuse for Issei to see her in tight pants. She front flipped onto the slide, stretching her legs until they were behind her head, allowing her to lick herself as she slid down. Akeno was amazed by what she saw. Rias slid into the pool and dove out from under the water and back onto solid ground, bowing as if she had just done an olympic stunt.
"Damn, girl. Ten out of ten. Stylish, sexy, great form at the end and...you have to teach me how to do that." Akeno said.
"I'm sure Issei would love you in yoga pants." Rias joked.
"Well, it looks like a tie." Akeno said. "I guess we'll settle it by going down together. How will that work?"
"First, we do your idea for a pose and then mine and then we each grade the other's idea for the pose after we do it." Rias explained. "If it ends in another tie, I guess we'll just have to eat each other out underwater at the same time."
"As much as I'd love that, I intend to win." Akeno said.
"As do I." Rias countered. "Now, what pose do you want to do?"
Akeno whispered in Rias's ear, knowing Issei would be listening and wanting to surprise him. Rias cooed at the naughtiness of Akeno's mind and nodded yes to her idea. The girls lined up in front of the slide and managed to get into a 69 position as they slid down, licking each other's pussies all the way. They fell into the pool, holding onto each other as they lapped at their rival's cunt, not stopping until they both came, afterwards they let go of each other and emerged, flipping their hair and splashing the other girl.
"That was amazing." Rias said. "10 out of 10!"
"Okay, hun." Akeno said. "Now, let's do you pose."
Rias moved Akeno's wet hair out of the way of her ear and whispered her idea into it, making her rival giggle. They got out of the pool and in front of the slide, this time lining up in a tribbing pose, Akeno in front, Rias in back. They locked thighs and rubbed their pussies and tits together as they made out passionately and slid down the slide, maintaining the pose until they fell in, amazingly, still not breaking their passionate, tongue-sucking kiss. They continued their underwater makeout session for five minutes until they came back up, again, splashing each other with their drenched hair.
"Fantastic." Akeno said. "10 out of 10".
"But, honestly..." Rias said in a reluctant tone. "Your's was better. We got to lick each other underwater regardless of who won."
Akeno cheered and gave Rias bedroom eyes as both girls giggled and knew what would come next. Akeno got up on a piece of the pool that jutted out while still being underwater, spreading her legs for Rias to dive in. Rias inhaled and went underneath to lick Akeno's pussy. Akeno moaned as Rias tongued her savagely. She put her hands into Rias's hair as it flew around underwater, enjoying her rival's mouth bobbing on and nibbling her clit. She pulled on Rias's luscious, wet, red locks as she ate Akeno out ravenously before the slutty raven finally came after five minutes of pussy eating. Akeno panted as Rias came out from under the water and smacked Akeno in the face with her heavy, wet hair. The girls giggled as went back into the water, soaked their hair and began smacking each other with it playfully, before they came together and shared a loving kiss.
"What's next?" Akeno asked as she licked at Rias's mouth.
"Squirt gun fight?" Rias asked.
"You're on."