Brattiest ticklee ever

Ako and Riko were hanging out at the beach minding their own business until they ran into Reina, a spoiled brat who was playing with her volleyball and accidentally knocked Riko's soda out of her hands, but instead of apologizing she just said "Hey dumbass, don't stand around near my area!" as she picked her ball back up. "Who does this girl think she is?" Riko says, her sister tries to calm her down "Come on, Riko, let's just leave this brat to herself and-" then Reina hits the ball and sends it flying towards them a second time, this time hitting Ako's face.

"... You're dead, kid." Ako mutters, then Riko grins and the two charge at the girl, who tries to run away but ends up getting caught by the twins, one of them was already enough to overpower Reina, but the two going at her together made it impossible for her to get away. As they tie Reina up to one of the beach's playground devices, turning it into a makeshift bondage device, they take a good look at her. "What are you doing? Get me out of here now! You're going to regret this!" she demands, Ako and Riko just laugh at her.

"She's actually kinda cute, isn't she?" Riko asks, Ako nods and adds "Yeah, but I think we need to help her improve her mood a little..." as they look at each other and then at Reina. "Y-you creeps, what are you gonna do with- EEEEEEK!" before Reina can protest, she feels Ako tickling her tummy and squeals, her attempts to stop her completely futile. "Hmm, would you be ticklish by any chance?" Ako asks, Riko tries helplessly to stifle her giggling and answers "N-no, I'm just... argh! Hihihihihi!" much to the twins' amusement. "Really? Then I guess you don't mind me just being here and giving this cute little tummy of yours some scratches, right?" Ako says as she uses both hands to tickle the girl's belly, she laughs harder. "Kyahahahaha stop! I am ticklish, is that what you- ahaheheheee! What you wanted to hear?" Reina's words make Riko grin as she then moves in and tickles her armpits from behind. "AHAHAHAHA! NO, WAIT, NOT THERE, PLEASE!" Reina bursts into laughter and begs as Riko tickles her armpits even harder.

"Ooh, not there? You know this basically means 'Yes, tickle me right there!' to us, right?" Ako says as she also moves her hands up to tickle Reina's armpits along with Riko, the two torment her armpits for what felt like an eternity for the girl. "You know what, her feet look like they could use some love too." Riko says as she then moves down, Reina says "N-no, please, that's like, the second worst spot!" and Riko just laughs and says "Oh girl, you make this way too easy for us...", the twins completely break the poor girl, leaving her sobbing and gasping for air after they're done with her.

"Haaa... haa.... get me... out of here... now..." a completely exhausted Reina says, Ako responds "Should we? I dunno..." and Reina responds "Do it already, you creepy bitch!" and Ako goes back to tickling her armpit, "You're not the one in control here, girl!" making Reina revert back to the laughing mess from seconds ago. "Come on, Ako, I think she had enough, let's go grab another drink." Riko says, her sister nods and the two leave Reina there, the girl is dumbfounded "W-wait! You're gonna just leave me here? Untie me, now!" her protests ignored by the twins walking away.