Her panties drop

Sandry looked down at her book, fighting to control her blush.

"Sorry, miss, I..."

TWANG!

She never thought such a small noise could be so horrifying, but as she felt the cotton start to slip down she was filled with dread.

Not quite quick enough, she failed to stop her knickers falling and her large, pale buttocks being exposed to everyone behind her.

"What on earth...?" Miss Lane exclaimed.

"My elastic snapped!" Sandry cried, grabbing for her underwear with one hand and trying to cover her privates with the other, too slow to prevent anyone close to her getting a look at her neatly trimmed pubic hair.

Having grabbed them, she found them **** to come up, the red cotton somehow twisting and tightening around itself, coming to a halt halfway up her thighs. Her backside jiggled as she struggled with her underwear, desperately trying to cover herself again.