Aoi had asked you for a favor and you said yes, so she has you holding a stopwatch, checking to see if she can best her own best time at swimming 3 laps. She changes into her swimsuit and begins...
An hour later, Aoi has been swimming for a while now, and she managed to beat her best score by a few seconds, which is amazing!... At least, for you. For her, she sees it as a new record to beat. She changes back into her normal clothes and walks with you to the cafeteria no one else in there except you two.
"I'll beat my new record... but first, some donuts!"
You watch as she rushes over and has a donut or two, though, as you watch her enjoy herself, you see her diaper obviously bulge in her daisy dukes... she made a mammoth bowel movement in there, and she doesn't seem to notice!
"Hey, you want a donut too? There's a chocolate one right here!" She says, as she holds a donut out for you... Chocolate? She couldn't've said that at a worse time...