They notice her discarded towel

(chapter originally by Misayaka on writing.com)

The conversation then took a strange shift in tone. They were no longer talking about idle gossip... instead they had begun curiously commenting on a strange object lying on the floor. Chihiro silently hoped it didn't mean what she thought, but it hadn't taken long for her fears to be proven warranted.

From where she sat, she could see the end of her discarded towel being pulled up from the floor, along with her only hope of finding any cover.

Despite the alarming loss of the undone fabric, she tried to stay calm. They had no way of knowing where it came from, and especially not that it came from a girl in their bathroom, did they?

It helped Chihiro steady her breathing, until, after finally regaining her composure...