A magical tingle ran through Perci's insides, and her belly bulged.
"Uh, I feel bloated..." she started, her hands on her lower belly. After the feeling subsided, she pulled on the waistband and saw a perfectly smooth, rubbery slit.
"Did it work?" Eva asked nervously, her dolphin penis still exposed.
Perci slipped a hand inside the bottoms, caressing her white and black slit. A pink nub started sliding outside, and she rubbed her palm over her groin to coax it out.
"I think it's working, yeah! I... AAH!" Pierci yelled as the protuberance thrusted forward brutally. It tented the bottoms to their maximum before tearing them apart, destroying them completely!
Perci tried to hold on to the cetacean member as it twitched violently and grew outward. Its flesh swelled as it left the confines of her insides, her belly flattening while it expelled more of the penis. She fell on her knees, trying to hold the thick monster still, but the tapered end kept spasming and extended until her member reached two feet and a half in length.
"Help me!" Perci whimpered, overwhelmed by sudden arousal.
Eva threw herself to the floor, attempting to sit on Perci's penis to hold it down - and barely succeeding. Perci became extremely flustered as she felt Eva's touch and weight on her member, which began oozing pre under her friend. Eva herself was not in a better position, her dolphin penis twisting around on itself and frotting against Perci's.
Perci opened her mouth but failed to warn her friend in time. She let out a lewd moan as her orca penis jerked, a burst of cum splattering under Eva and over the tiles. Almost simultaneously, Eva's dolphin cock stiffened upward and a surge of fluids sprayed the two girls' chests.
"I'm... I'm sorry!" Eva stuttered between two whimpers, jumping back on her feet to aim her penis away.
Perci, still shook, sat silently in the puddle of cum for a moment. Her giant penis softened and slowly slithered back into her slit, barely contained inside her feminine body. The little bulge of her belly was the only telltale of the monster which rested back inside.
She stood up, putting on her bikini bottoms with trembling hands.
"Thanks for the... help" she finally said, blushing a little. "I think we should go to the swimming pool before anyone comes for us."
"Do you have spare bottoms, Perci? I can't just... go like that" Eva gestured at her alien slit.
Perci rummaged through her bag and handed Eva her regular swimsuit. She did pack it along with her bikini, after all... probably just in case coach Emily would not accept the revealing bikini at all.
The swimming suit was a bit loose on Eva, as she didn't have as much curves as her friend Pierci, but it was still a better option than exposing her dolphin slit for the world to see.
The two friends walked to the pool quietly, words lacking to talk about what had just happened. They arrived just in time for coach Emily's instructions; then everybody jumped in their own lane for today's exercice.
The hour passed uneventfully and as the swimming session concluded, Eva was letting herself fall back into the usualness of the day...