(F) You immediately start using it.

Before you can stand up to perhaps grab a drink of water or a snack to sit down and wait until you had to go, like you originally figured you'd have to do, you're startled by a sudden leaking, drops of urine seeming to leak into your padding out of nowhere. Your heart races as you're for some reason unable to clench your muscles properly, only allowing more piss to spurt into your padding. Your cheeks burn hot as your twitching bladder releases more piss until it fully releases, a tear rolling down your cheek.

The heat in your face and the racing of your heart are quickly complemented by a growing throbbing in your pussy as piss gushes into your thick diaper, drawing out whimpers and shivers. Unconsciously, you start grinding, even as more urine soaks into your padding, and the realization makes you freeze momentarily.

Your self-restraint is short-lived as you feel an odd mass growing in the back of your diaper, which you realize is your own shit, that you can barely feel even escaping your bowels. You're not even noticing when you're starting to go right now, like a totally unpottytrained baby! You whimper again, the seat of your pants filling with shit at an alarming rate, and you add more moisture to your padding in the form of your juices.

Your heavily used diaper squishes and stains further as you grind into it, whining and whimpering to yourself about how much of a pants-pooper you are until it draws out a scream, orgasm rocking through your body until you're a shuddering mess, drenched in sweat and piss, and diaper packed to the brim with your shit.