All the names used have been changed for anonymity. None of these are 
the real person.

A few years ago, my mother was good friends with this woman who had a 4 
year old who was still potty training. Just before Candy (the 4 year 
old girl's mom) had finished getting Amanda (the girl) potty trained, 
she invited my mother and me over for the day. I played the X-box of 
Amanda's brother Phil's until about 7:30, when my friend Helen arrived. 
She knew about my fantasies and didn't mind. We eventually got into a 
bet that I couldn't sneak one of Amanda's Pull-Ups out of the house. I 
proved her wrong; I merely put the pull up in my pants. After we left, 
the Pull-Up now under the seat of the car, I was the last one to get 
out; I needed to get the Pull-Up unnoticed. I somehow managed to get it 
into my room undetected, which was a relief. I then needed to get it 
into the basement, which was where my video games were. I decided to 
wear it. It turns out that I was so skinny, that there wasn't even a 
diaper bulge under my pants. I went downstairs with it on and played 
video games for another hour, when I had to go pee. I wasn't sure I 
wanted to use the Pull-Up right away, but my body made the choice for 
me. I wet the pull up thoroughly, though with no leaks. It didn't even 
sag. I eventually went to bed with the soaked Pull-Up still on. 

I woke up feeling dazed, as we all do. I realized the pull up was still 
on, but I still couldn't see it even in my thin pj's. I went downstairs 
before anyone woke up and played more video games. Then something more 
urgent than peeing hit me; I had to poop. I normally didn't poop in a 
diaper or pull-up, but this was going to be my first. I found an old 
sleeper in a bag in the back room from when I was 2. I still fit in it!

It was a tight fit, so I knew that when I pooped, it was going to be 
very messy. Surprisingly, it didn't take much to poop and it squished 
up against my back and front. I suddenly realized that my family would 
be getting up soon, so I got out of the sleeper and put it away, but I 
couldn't bring myself to take off the pull-up. So I ran to the spot 
where my video games were and covered myself in a blanket I kept there 
in case I was cold. An hour later my sister came down to do the 
laundry. Being 11 and naive, I didn't think she would smell the poop in 
my pull-up. She walked over to my wondering what the heck that smell 
was, when she realized it was strongest near me. I sweating bullets 
didn't help either. She pulled off the blanket and saw me in just a 
pull-up, which was now obviously full. I had also wet it from fear. She 
yelled at me for a bit, saying how disgusting that was and she 
threatened to tell my mom. She left the room so I could change myself 
and get cleaned up. Since then, I have not been caught. I still wear 
and use them sometimes, but she has never found my stash (maybe because 
they aren't in the house).