I started messing my pants before puberty and before sexual
feelings. I just enjoyed the warm feelings. I used old
underpants, towels, rags, and other cloth items rather than
diapers.  Then I discovered masturbation and also discovered that
messing my pants gave me an erection. It took no time at all to
combine the two activities. I was doing this only when I was
alone until the day I was caught by my best friend Roger.
     I had the house to myself so I planned for a poop and pee
session. I used an old towel that day, pinned in place like a
real diaper. I left it a little low in front so I could play with
myself during my fun. I had to go poop pretty bad so I knew this
was going to be a good time. I arranged a kitchen chair over the
dining room linoleum so any pee that dripped out of the diaper
could be easily cleaned up. I then walked around the house
becoming more aroused by the minute. The walking also increased
the need for me to poop. I had peed in the toilet earlier so as
not to make to big of a wet mess in the house.
     Soon the urge to poop became very strong. It was all I could
do to hold it. I relaxed just a little bit and felt some poop
start to come out. I then squeezed myself shut to stop it. I did
that three or four times. I could feel a small deposit between my
cheeks, and by now I couldn't hold back anymore. As it oozed out
of me I just relaxed completely. I filled the makeshift diaper to
capacity in seconds. I stood there for a little while forcing out
any remaining poop. Then I reached behind me and felt the big
load I had deposited in my diaper. I pushed it against my ass.
     I sat down on the chair and enjoyed the way it squished into
my crotch and all over my butt. It felt nice and warm and gooey
like it always does.  As I sat there in my poop I took out my
hard cock and started to stroke it. That is how I was sitting
when Roger just walked in without knocking. I was facing the door
so there was no way  to avoid having him see what I was doing.
But he didn’t know about the messy diaper until he approached
closer.
     He sat in another chair as I just sat there frozen, my cock
still in my hand, although softer now. He asked if I liked doing
that. I said liked what? He said jerking off. Then he told me
that he learned how to do that a few months ago but didn't want
to tell anyone. I told him to do it now with me. He stood and
dropped his pants and underwear. He pulled the chair over in
front of mine and sat back down with his hand stroking his
growing cock. He then asked my if I had pooped my pants. I told
him that I had. He asked why and I told him that it felt good. He
said he would like to try it sometime.
     I saw my chance to keep us even and not be so embarrassed so
I got up and found a towel and pins for him. He took off his
pants and shorts and I helped him get his diaper on. He stood
there for a little while with his diaper and then I saw a wet
spot spread from his crotch. He was peeing in it. So far so good.
He smiled and then filled his pants. He pooped a lot just like I
had. He asked me what he should do and I told him to just sit
down in it. He did and said it felt pretty neat. We then sat
there facing each other and began playing with our cocks again.
     Roger shot first and when he did the cum shot over and
landed on my legs. He laughed at that. So when I came I aimed at
him and got my juice on his legs. We both laughed then. When
things started to cool off I told him to get in the shower and
wash himself up. I waited in there and took the messy diaper from
him when he removed it in the shower. When he finished I got in
and took off my diaper. He took it from me and waited while I
cleaned up. We then got dressed and cleaned up the chairs and
floor and took the used diapers outside. We buried them in the
field near my house so they would never be found.
     After I discovered the enjoyment of messing my pants and
then discovering the enjoyment of masterbation and discovering
that my best friend also enjoyed pooping in his pants, things got
really fun.
     Roger and I would get together at his house or mine, and,
using old towels, rags, or a couple pair of old underwear we
would diaper ourselves and fill our pants. We discovered that if
you didn't have to go, if you would gently pound at your ass with
the protruding thumb of a fist, you could induce the pressure of
pooping. Usually though, we didn't have a problem. We never
touched each other during these sessions. (That was to bad,
looking back on it now) But we would watch each other mess our
pants and then sit together and masturbate. It never dawned on us
to masturbate each other.  When the warm, gooey, feeling went
away, we would take off our homemade diapers and clean up. Then
we would dispose of the poopy rags out in the fields surounding
our houses.
     One winter we had buried many poopy diapers in the snow and
when spring melted the snow, there they all were. We had to take
shovels and bury them before someone found out what they were. We
were pretty amazed at how many had accumulated over winter. We
had been busy teens.
     One afternoon, we had just finished our session and were
cleaned and getting dressed in the living room. Roger dressed
first and went into the kitchen. Suddenly he said "oh hi Mom". I
thought he was kidding and was going to go into the kitchen to
laugh at him with my pants still down but something told me not
to. I continued to pull up my pants and as I was zipping them up
in walked his Mom. She saw me pulling up my zipper but other then
that we were all proper. She called my Mom and told her we had
been up to some sort of mischief. She probably thought we were
jacking off together. Well we were. If she had any clue about the
messing our pants she would have gone balistic. We used my house
for a while after that close call.
     We did our thing down at the lake in the summer. We would
poop our swimming suits and sit it them and walk in them and then
wash them out in the lake. (not politicaly correct, I know) We
had fun with it until I went off to the service. When I got home we
still hung around together but never mentioned or did our messing together again. I
wonder if he still does it? I haven't seen him in years.

I still enjoy it.