A dog collar.

As the locker door opened, a dog collar came into view as Miki took the tool out from the locker, locking the door as she held the collar in her hand.

'I've been thinking about it the whole time... and today I can do it!' This was Miki's idea of a birthday suit, and it wasn't the first time she had gone streaking like this either. She has gone out in her neighborhood, streaking while wearing only a dog collar, but this is the first time she'll be doing it in public, per se.

Opening the collar, she would wrap it around her neck, before fastening it loosely, which would help at least give her enough room to breathe properly. Walking down the hallway, she looked for a place where she could undress and put her clothes away.

There seems to be a few locations that Miki could possibly place her clothes at.