Just as the swimming lesson had come to its end and Riley was about to get out of the water, she felt strong cramps in her guts. Her body tensed and she clinged to the pool's edge, her chest pressed against the tiles.
A shiver ran down her spine, her heart beating fast. With each thrum, she felt as though her swimsuit was tightening around her body a little more, until underwater the vertical tiles of the pool came in contact with the curve of her swelling belly.
"Are you coming?" Piper shouted, already walking to the showers in a hurry.
Riley slowly climbed out of the pool, waiting for her classmates to go ahead, her arms hugging her body to hide her curves. The swimsuit was digging into her hips now, and her breasts were spilling out on the side if she was not careful. Most of all she felt bigger, her belly suspiciously bloated.
She awkwardly walked to the showers, trying to turn away from the girls that were still there. Piper was nowhere to be seen, probably two step ahead. As the water ran on her body, Riley could tell her breasts were quite sensitive, as well as the canine nipples hidden in her suit. She hurried to pick her stuff and go to the bathroom so she could change unnoticed.
Once in the stall, she removed her swimsuit to inspect the damage. Her breasts spilled out, the dark areolas puffed up obscenely. She removed the medical tape that covered her canine teats and they sprang forward, the areolas swelling with them. Caressing her body in the stall, she noticed how mature she looked, with wider hips and a rounder butt.
She put her hands on her bloated belly with a mixture of shame and... pride? She looked womanly and gorgeous.
She started putting on her clothes, squirming to get inside her small panties, adjusting her skirt so that the waist wouldn't constrict her too much. She tried to pull her bras close but the cups were too small, the band too short, so she shoved it in her bag in annoyance. She was buttoning her shirt when she heard a knock on the stall's door.
"Riley, are you there?" Piper voice echoed in the deserted bathroom. "I'm coming."
Riley jumped in surprised as Piper pushed the unlocked door open, closing it on the two of them like they sometimes would on lunch break when meeting secretely to touch themselves. She didn't have the time to react when Piper threw herself at her, kissing her without restrain.
"Oh Riley, I couldn't wait to be with you again! You look radiant today..." Piper let out in a whisper as their bodies pressed against one another. Riley tensed when she felt Piper's belly brush her own, but relaxed when their breasts squished, barely contained; she had to admit it was a pleasant feeling. Just like her, since exposure to the vial, Piper had gone through a growth spurt and she was more attractive than ever.
However Riley didn't know that, also just like her, Piper had been impregnated by one of their friends. Though her friend's belly didn't seem as bloated as hers for now, the curve had accentuated since the previous day, and hips had grown as well.
A moan escaped their lips as they rubbed their bodies together and kissed, nipples poking through the fabric of their shool uniform, their imperceptibly growing bellies pressed together. They blushed, each thinking about their predicament. "I don't know how to tell her Erika filled me up," Riley admitted to herself. "She can't know I rode little Emily until she cummed" Piper thought in her own mind.
At the same time, the idea felt not only naughty but also exhilirating. These new sensations were addictive and neither of them wanted to stop. As the heavy petting intensified, they heard moaning rise from the next stall.