A pressure on your bladder makes you look around. Spying a small stone building just off the path you see the familiar set of symbols indicating a pair of public rest rooms. Feeling grateful you push open the surprisingly heavy wooden door with its peeling brown paint, and enter the cool, slightly damp interior.
You barely glance in the mirrors over the ancient sinks-- you hair is somewhat disheveled from being outside, you need a shave, and the t-shirt you are wearing is on its way to becoming a rag-- but its your day off, so who really cares anyway?
Striding over to the urinals you see some kid has left his clothes draped over the privacy shield between the urinals and the sinks, and that there is an "Out of Order" sign on the adult height urinal.
Shrugging, you step up to the child height urinal, and start to relieve yourself.
The feeling of relief is so strong you shut your eyes with a feeling of satisfaction..., and keep peeing. And peeing. And peeing. You start to wonder just how big your bladder was swollen! You could swear you have released more fluid than you drank today-- or even all week! Finally the flow lessens, and you open your eyes.
The handle of the urinal is now just below your eyes. You could have sworn it was much farther down-- maybe you stepped up to the adult urinal without realizing it? Even so, the handle shouldn't be that close to your face....
You go to zip your fly, but as soon as you let go of your penis, your pants fall down around your ankles. Bending to pick them up, your underwear joins your pants around your feet, and you find that your t-shirt is now down to your knees.
"What?! What's happening to me?!?" you exclaim, realizing that the rest room is much bigger than you remember. Pulling up your shirt, you see that your dick is now a tiny, child's one, maybe an inch long (if you are lucky, that is), and your scrotum is smooth and hairless, your balls having retreated into your body. Your legs are also free of hair, and your feet are lost in your shoes.
Looking around in panic, you try to think of what you should do. If you try the adult sized urinal, will you return to your correct age? On the other hand, the boy's clothes look about the right size for your new age.
Hearing someone opening the rest room door, you realize you need to decide NOW!