Have to say Im a very boring person and dont have one. My mum, uncles, aunt and 2 cousins have them and I remember my mum saying I was forbidden to have one, then she showed up with one!
I seen a woman afew years ago at a Biffy Clyro concert and she had small stars scattered over her hands. She said they were only temp cause it could prove difficult to get a job if they are on show.
But my cousins, aunt and mum have them on their backs and I mean, why have them there?! You cant show it off unless you wear a costume, bikini or are willing to take your top off to show it off!
Have you got any?