I know Mavis from an internet forum where he liked to share his art. He never made it a secret that he did commissions nor that he had fun drawing adult material. One day he posted about a sale on his normal commission rates, and I who had had a recent half-asleep philiosophical dream wondering why, the Lady of the Lake from the King Arthur tale was usually depicted as a human rather than actually made of the lake, decided to pay him to draw it for me.
This piece from August 2018 was the first. There is also a "nsfw" version of this.
Some of the ways to reach Mavis for commissioning your own work: