Well, about 22 years ago, when the internet was still young, people introduced me to a little game called Runescape. One of the amazing features of Runescape is you need an account name. This was my first exposure to the concept of being whoever you want on the internet, so I was quite amazed that not only could I pick any name I wanted, but I actually couldn't pick my birth name because it was already taken.
Now faced with the infinity of alphanumeric combinations available to me I thought "what do i like... Pokemon!" The main protagonist of the Pokemon anime was Ash Ketchum, so i made my name Ash2000456. Ash was also taken already so I though "you want numbers? I'LL GIVE YOU NUMBERS!"
Now I've had many nicknames throughout the years, but Ash has always stuck around. So as I delved into the kink world, I decided Ash was a perfect name. A little androgynous, a name I've come to identify with outside of Pokemon, could be short for Ashley, which is one of my favorite female names. It's also a phoenix metaphor, not just rising from the ashes of my not so good childhood, but wearing the ashes as a lesson, a warning, a message.
But Ash is still a very commonly used name, so on most platforms there's already an Ash staking claim to my sacred name. Thus i attached an adjective relating to my first kink. So began the legend of Messy Ash. And my friends took to calling me Ashy. that is how MessyAshy came to be.