I know, it's not a tattoo, but it's funny. I assume that the poor kid has absolutely no idea about the meaning of the ideogram imprinted on his sweater.
What doesn't know the lucky owner of the sweater is that the ideogram means "piles, hemorrhoids" (both in chinese and in japanese). Fortunately for him it's easier to get rid of a sweater than it is to get rid of a tattoo.
Now, I would like to give you an advice: if you want to decorate your skin (or your clothes) with ideograms (Kanji or Hanzi) you should avoid the ideograms which contain the radical depicted in the image below:
This radical means "sickness" and the kanji / hanzi composed with this radical are usually associated with diseases, sickness, illness, etc (e.g.: 疔 = ulcer, 疝 = colic, 疥 = scabby eruption, 疣 = wart, 癢 = itchy) - in short, not the kind of words that one would normally choose for a tattoo.
There are several ideograms composed with this radical which are not related to illness and diseases, (e.g.: 疾 = fast, rapidly) but there are very few and, unless you are absolutely sure about the meaning of the ideogram, it's better to avoid the Kanji / Hanzi which contain the above-mentioned radical.