I haven't made any although I have thought about this in the past. The problem for me was choosing which system to work with, I did tons of switching between several.
I think any permanent marking should be after careful thinking. The symbolism should be connected to the path you work with. If you are unsure then it's probably not a good idea. Wrong symbolism could lead to strange problems. I think lots of it is very individual. I recall some specialist mentioning that a square, triangle etc could be bad for one but beneficial to another. Lots of details of all kinds, can't remember.
Really
@Morell ? Knowing your deep interest in vampirism I was expecting a large Dracula covering the whole back side. Maybe even VFFV, vampires forever forever vampires with some drops of blood and maybe a chalice.
I've seen something rather weird speaking of tattoos. There was a guy with his entire back of the head covered with a goat and inverted pentagram. Everybody stared. This guy sat somewhere at the front of a bus. Not sure what goes through the mind of somebody who gets one like that.