[A multi part story inspired by my own experience. The first part which is story set-up is basically entirely true from my own perspective (Emily represents my perspective, other characters' thoughts imagined). In this telling every character is at the end of high school so 18 or over]
Following the most embarrassing class in Chris's school life so far, not only did he have to endure ridicule by his classmates, but also a detention for breaking the rule "no petting in the pool." What did that even mean? The detention took place Friday lunchtime before the gym class at the end of the week. "Hi Chris" said Emily playfully as she arrived with Madison outside the coach's office.
Chris looked down at the floor and said "hi" quietly, too embarrassed to look them in the eye.
Coach opened the office door and said "ok you three, get changed into your gym kits and meet me in the gym in five."
The three students looked at each other. "We didn't bring them coach, we didn't realize we needed them."
The coach sighed. "Bring gym kits to all gym detentions. That's the rule. So you've earned yourselves another detention. For this time I'll bring you the spare kit, wait here."
Chris glared at Emily and Madison. It was their fault he was here at all, totally unfairly, and now he'd have to have another detention as well! Madison looked away shyly, while Emily just smiled.
Coach returned. "Only two sets of spare kit left" he said, passing them to Emily and Madison. "Chris you can use your swim shorts."
Chris changed into the swim shorts, over his boxer briefs, and kept on his school shirt. He walked out into the gym, looking a bit silly in a buttoned shirt and small pair of shorts, and met the girls who wore school shorts and t shirts, and they waited for coach.
Coach came in and said "ok I'm going to work you hard here to teach you a lesson. Get the weights out the cupboard and set up the horizontal bar. And Chris, take that shirt off I don't want you getting it sweaty!"
Emily whistled and Madison blushed as Chris took the shirt off and folded his arms to cover his chest, once again feeling vulnerable. This was so stupid, he thought. The girls could've worn their swim tops and he could've worn one of the spare gym shirts. But feeling the girls' lustful eyes on him was already making him feel horny, and Emily tracing her fingers over his bare back in the gym cupboard didn't help either. Luckily, his underwear was keeping his erection down, much to Emily's disappointment as she kept glancing down at his crotch.
After they'd got the equipment out coach made them do 20 laps of the gym to warm up. "Ok ladies, take a break. Chris, 10 more!" Every exercise coach made Chris do more as boys always had to do more reps, which provided Emily and Madison with the perfect opportunity to watch his hot body in action. His abdominal and chest muscles looked so defined as he did his sit ups in front of them. Chris could feel their hungry eyes on him, and felt more exposed than ever. They also did pommel horse and weight lifting.