Trying to think of a situation where you would have one unwillingly
My birthplace tattooed on my 'member'. Ah, I have such fond memories of Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch
I'm a bare canvas but have a real thing for Russian Criminal Tattoos after seeing an exhibition at the Saachi gallery a couple of years ago. The show was based around an extended study made by a Tartar prison guard and ethnographer, whose own back story is worth the effort. There are a couple of books that I've bought and I've learned to pick my way through the Cyrillic alphabet, if not the language.
The books explain the meanings in detail, but broadly the tattoos are used to denote rank, sentences, places of incarceration, crimes and back-story within the underworld. There are a huge amount of offensive, fascist, racist and pornographic tattoos, but the real meaning is often not what you'd first expect - for example swastikas are quite common but usually signify a "f*** you" to the authorities, rather than overt support for the third reich.
So, eventually getting around to
@Julia9054 's observation, one form of tattoo is forcibly applied to criminals that have violated the underworld code, for example by failing to pay a debt or being a suspected grass. These will usually be objects that denote low rank or shame - hearts, ladies shoes, brooms and other weird objects. Also, if you're found to be sporting a tattoo that you haven't earned, it can be removed using something abrasive (brick dust, sandpaper) or just amputated (common for ring tattoos).
And on to
@Fnaar - 'intimate' tattoos are also common and the books have a few photos that can't be unseen. The Soviet 'Made in the USSR' symbol is quite common.
If you're interested, here's a
link to the site associated with the books, but fair warning, they're NSFW and many are offensive.
