The lesson ends

Eventually the game ended and Sandry gratefully hurried back to the changing room.

"Nice moves, Sandry!" one of the girls teased.

"I didn't know it was supposed to be shirts versus skins!" another added.

"Yeah, ha ha." Sandry replied dryly, tugging her blouse around her. It felt even tighter now she had no bra holding her breasts back, and she had a horrible feeling her nipples were visible through it, but it was better than the nothing she had been wearing. Trying to suppress the grunt of effort, she fastened the small buttons.

She picked up her skirt, stepped into it, wiggled it up to her waist, and pulled up the zip.

RIP!

The zip came away from the fabric and the back of the skirt parted in a wide oval, revealing the split in Sandry's knickers again.

"Oh no!" Sandry whispered, clapping her hands to her bare buttocks, "My bum's out again!"

The laughter from the rest of the girls told her this had not gone unnoticed.