"To have your seed pony tattooed just post in the appropriate board at the seed pony forums with these questions answered:
Where do you want the tattoo? (ex: hoof, check, right front leg, etc)
What do you want the tattoo to be? (anything within reason)
No tattoo will be alike so please do not request one that someone else has. If you want something similar that's fine. For example, if one seed pony has a rainbow tattoo you can still ask for a rainbow, it will just be a variation on that theme. Example images would be helpful if I don't know what the object is.