Jenny went into the locker room at school and changed for her gym class. When the other girls finished, they left, and she stayed behind. She went into her book bag and brought out the bra which allowed her to inflate herself. She put it on and went into the janitor’s closet next to the locker room and locked the door. Inside she spotted the helium tank used for the school dances. She placed her mouth on the hose of the tank and turned the valve on. She felt the good sensation as the helium rushed into her chest. She looked down to see her B-Cup breasts balloon out to a C. Her X-Large tank top, which was way to big for her was shrinking as it made room for her growing boobs. Her chest rose to two volleyballs. She bounced a bit to see if they were large enough. Not yet. Her breasts expanded a bit more and then she felt herself lifting off the ground a bit. She turned the hose off and pinched her nipples to let some of the air out. She went over to the mirror. The tank top fit over her watermelon sized tits perfectly now. She left and ran down the hallway to the gym, her helium breasts bouncing merrily as she ran.
It was CO-ED day and she wanted to have some fun. The girls side of the gym had a variety of gymnastic equipment, and on the other, a basketball game was going on. She walked over to the trampoline. As she walked, the boys at the basketball game and the ones sitting on the bench stared at her bouncing boobs. Even the female gym teacher couldn’t help looking at them. The girls in her class were a bit jealous and a bit confused on how she got her huge chest.
“Has anyone ever hit their head on the gym ceiling?” She asked the female gym teacher.
“No. No one’s ever going to go that high.” She said.
“You sure?”
“Positive.”
“Okay…”
She got on and started plain jumping. She made sure she wouldn’t go high during the first few jumps. She did a couple of flips and during them, she took deep breaths to make her breasts a little bigger. She stopped jumping and looked around, her tank top was now stretching under the pressure of her breasts. They were starting to go upward a little bit. Everybody was now staring at her massive tits. She started jumping again, this time, the helium in her breasts pulled her up even higher. Soon she was able to touch the rafters of the ceiling. For a bit more show, she did a flip and went between the rafters. When she landed, her teacher could only gape at her.
“I think I’ll play some basketball now.” Jenny said skipping over to the boys. They were continuing their game.
“Hey guys.” She said rubbing her enlarged breasts. “Can I step in?” They stopped their game again and watched her fondle her ballooned boobs. Three of the guys ran to the bathroom while the others began to drool a bit.
“Sure. You can play.” One of them said. “And afterward, how about being my date tonight?”
“I’ll think about it.” She giggled. “Let’s play!”
They started into a new game. She got the ball a few times, but the rest of the times, it bounced off her breasts. She even flattened another guy with them to steal the ball. She then ran back to the three point line. She noticed the weirdo under the hoop was wearing a spiked dog collar. She got an idea.
“Watch this!” she yelled running towards the hoop.
She jumped and in mid air, her helium breasts picked her up higher and higher. She performed a fancy slam dunk that looked better than Jordan’s dunk. She fell on the weirdo and his collar popped her tits.
They all gasped. “Hunh?”
She glanced down. Her breasts were back to normal.
“Tee-hee! Bye guys!” She said running off.
“The date’s off!” The one boy yelled.
“Go blow yourself you prick!” She yelled back smiling.
“I think I’ll go buy some more bras tonight.” She thought to herself.