She's a bedwetter

Marinette had invited several of her friends over for a sleepover to celebrate Summer Vacation. After a fun night of games and laughter, everyone started to get ready for bed. Just as Marinette went to the bathroom to brush her teeth, she was stopped by her friend, Mylene.

"Uh... Marinette? Can I ask you to do a favor for me?" Mylene asked timidly.

Marinette had a warm smile on her face. "Sure, what's up?"

"W-Well, I have certain... problems at night, and I need... protection for it." Mylene hesitantly took out what looked like a white rectangle that Marinette recognized from babysitting.

"Mylene, is that a..."

"Please don’t say it!" Mylene squeaked out. She hated using the d-word. "It's just that... I'm not good at putting them on, so can... can you please help me with this?" She asked nervously.