[QUOTE=Tvataham274;2585349]I [I]think[/I] it might stand for HH. And in the context of white supremacy should be obvious what it means. But in Germany, of all places, that is incredibly illegal.[/QUOTE]No, a tattoo of "HH" and "88" is perhaps tasteless, but not illegal in Germany because this is code speak and could mean anything. The person in question might say some bullshit like "88 is my lucky number" or "HH are the initials of my first boyfriend" or whatever. That's the reason they have those tattoos because they are not illegal.
Even writing it out in full, provided it's used in the correct context (for example in a history book, or a documentary) would not be illegal. Writing down in full the real meaning of HH without any historic context however is illegal.