Tween at beginner swim lessons forced to wear a swim diaper like the rest of the class. The parent they 'borrowed' one from putting them in a proper diaper after class and fucking them hard on the locker room bench as repayment for taking two expensive diapers…
The added padding helpful for the eventual walk home, noticeable bulge disguising the real reason for the waddle to their gait and soaking up the oozing cum.