I've always had a thing for messing when I was a toddler, right fter I was potty trained I still enjoyed diapers. I'd poop in my mother's Maxi pads and hide them, not knowing what to do with them.
Later on when I reached pre-teen hood, I got the drive to start enjoying the soil in between my butt cheeks, because I'd feel the animalistic drive to enjoy soiling myself. So I would wrap up toilet paper and poop while squeezing it between my butt cheeks. This is what really began to give me the idea that it was a secure thing to soil myself and enjoy it. Coincidentally it was around the same time I began experimenting with masturbation, but the connection to masturbate after soiling did not connect yet, it just felt good, I didn't know where to go with it.
Around the same time, I was too afraid to buy adult diapers, so I began to create makeshift diapers. The first time I really did it was when I folded a lot of paper towels together and put them in my underpants, then let it go. It was an okay experience, I just felt embarrassed and insufficient being in a paper towel makeshift diaper. I later ended up looking around my house for things that were more comfortable to wrap around my waist, like old towels and old shirts. I'd pin old shirts up like a cloth diaper.