For Americans, and I suspect a fair number of non-Germans.....it won't make much sense after I explain the term.....so pause and try to think German in this case.
A Sitzpinkler.....is a guy who has taken to the habit of urinating while sitting. It doesn't matter if it's at work.....at the train-station....at the airport.....while shopping.....or in the pleasure of his own home. He sits and urinates upon the toilet.....rather than stand.
Where this comes from? No one talks of the origin much in Germany. The general belief (at least from me)....is that when out-houses started to disappear around the beginning of 1900s.....men and women had to share an indoor bathroom. Guys naturally had been standing for thousands of years and German women quickly put great value upon an interior bathroom, and the floor around it. So a guy happening to "miss" (even just a little) and leaving an tiny bit of urine on the tile-floor....it was a bad thing.
As years passed, German women (in my humble opinion) opted for direct authority, and established boundaries. This boundary thing meant that a guy had to cooperate and sit when he urinated.
A number of German guys are particular and feel insulted when this thing comes up. When their associates discuss their habits and it gets brought up that they are Sitzpinkler-guys.....well....it's an insult to the normal guy who stands. He'll let the Sitzpinkler associate know that.
Last year (2015), some legal case in Germany came to an end....over a renter and damages assessed against the guy. The basis of the mess? The landlord said that the non-Sitzpinkler guy had shot some urine onto the high-value floor and damaged it over the long-term. The judge heard the whole thing and finally declared that guys had the right to stand.....so they could possibly miss the target and it wasn't worthy of paying damages on the tile.
A stupid topic? I tend to think so, but I'm a non-Sitzpinkler guy.