She accidentaly tore her pants while stretching.

And so, Ren and Kasumi began on with their usual warm-up excercises, that ranged from simple stretchings to more complex gymnasy movements. While Ren was still getting used to practice those momevents, Kasumi had practically no problem in executing all of them with almost perfect rhythm and accuracy. After all, she was a national-level gymnast, she had those movements memorized to the core.

That said, even with how easy it was for her to do those moves, she wanted to push herself more and more to the limit, the last time she entered into a gymnasy competition she ended up in second place, which while good, it was still less than that what people expected her to achieve. And so, with that in mind, she was determined to go beyond her limits today.

"Now, let's do some more leg stretching", she said to Ren, as she once again, raised her leg as far as up as she could with her hand.

"Ehhh, doesn't that hurt ?, because it does to me", Ren commented as he tried to mimic the move in vain.

"O-Of course not..., i'm fine", she replied with an smile in her face, but in truth, she was having a lot of pain trying to strecht her leg as humanly far as possible, but that didn't matter to her, for she was determined to do it.

However, just then, just as she stretched her leg further and further up,something happened as a cracking sound was heard, not because her leg was dislocated, no, but rather, her training pants, trying to support the stretching, they cracked, leaving a rather big hole between her legs.

"Ehh..., Kasumi-san, your...", said Ren as he tried to explain to Kasumi what had happened, only for his face to become red and his words become scrambled as he saw her red and black panties.

"Y-Yes ?...", replied Kasumi still trying to do the streching, and unaware or the wardrove malfunction she suffered just now.