During an intense and epic battle between two sisters fighting at the school, Ryuko Matoi and Satsuki Kiryuin with their blades clashing together. they were getting exhausted from fighting for a while, panting as they put their swords away, Rico would clap for them and comes to them as they look down at him.

Rico: that was a really cool fight between you two sisters. Congratulations for making it awesome.

Ryuko: oh sup Rico. It pretty much was a pain battling my bastard sister, Satsuki.

Satsuki: Hello Rico. at least I had the upper hand on defeating you at the last minute you little swine, Ryuko.

Ryuko: who are you calling swine!?

Rico: hold on girls. I was thinking about that if you two would like to try something out? I think you both will love it a lot.

Ryuko: well... Sure we can try it out if you like

Satsuki: fine, I'll go with you two.

Rico smiles at them, grabbing their hands, and walk with them. Both Ryuko and Satsuki both looked at each other with angry expression due to their sibling rivalry, but then would blush and smile since they're walking with Rico. A few minutes later, Rico takes them outside of his house, and bring a helium tank towards them with two hoses connected to it.

Rico: alright, here's an air tank you both to use. This is where the fun part begin.

Satsuki: so just a helium tank? What are you going to use it for anyway?

Ryuko: are you planning on making balloons with it or something?

Rico: yep. I'm going to make you two as my balloons for today.

Ryuko: *blushes* what!? Seriously!?

Satsuki: *Blushes* hold on a second. Isn't it Juicy July like blueberry Inflation?

Rico: well you know what they say. You can't have blueberries without a bunch of balloons hehehe~.

Ryuko and Satsuki face turn red more in embarrassment as they both put the hoses in their mouths, and ready to be inflated. Rico turn on the helium tank and helium flows through the tubes and into their mouths. They were swallowing helium and their bellies expanding pretty fast, getting a lot bigger along with their butts and thighs expanding, showing their panties, plus breasts expanding like two large balloons. Ryuko and Satsuki float in the air with their expanded bodies bouncing against each other as they're now really large, inflated balloons as they moan in pleasure. Rico ties the balloon string on their wrists together, and pull out the hose from their mouths.

Rico: there you go sisters. You both are now balloons for the day~.

Ryuko: *muffled* wow. I didn't expect to be this big from inhaling helium.

Satsuki: *muffled* I'm not going to lie, I think this feel really good and satisfying~.

Rico: hehe I knew you both going to love it a lot. We can have a fun day like this~.

Ryuko: *muffled* I didn't say that I like it. It's just that... *Blushes* well fine, I guess I do love it~.

Rico: that's the spirit Ryuko. Let's have a fun, beautiful day since it's going to be the fourth of July.

Satsuki: *muffled* that's true. We should have our moment together.

Ryuko: *muffled* you're right. I totally love being inflated for this special day. We can see the fireworks too from up here.

Rico nod and carry his ballooned Ryuko and Satsuki together with the balloon string while the sunset down and it was night time. The trio both watch the colorful fireworks exploding in the air in the open field, relaxing while the two sisters enjoy being balloon toys for Rico, and their time on the fourth of July.