He said that when he was in history as a kid, his teacher told him that sitting bull's name wasn't actually that, but instead shitting bull. He went on, saying that it's reasonable because bulls don't sit unless they are sick. Also, the story went that in his dream to get his name, he saw a bull defecating, but the newspapers wouldn't run the actual name due to it being too vulgar. Can anyone find something about it, whether it's true or not?
There's plenty of issues with this:
The "pun" really only works in English. Sitting Bull's Lakota name, Tȟatȟáŋka Íyotake, does in fact mean "Sitting Bull" (a bull bison not cattle), and one couldn't really confuse "iyotake" for any of the various Lakota verbs for defecating.
Plenty of official government documents call him Sitting Bull, such as these two documents from the National Archives.
Sitting Bull's father had the same name, until he gave his own name to his son and was thenceforth known as Jumping Bull.
Most importantly, Sitting Bull signed his name "Sitting Bull," as can be seen on these two drawings of his from the Smithsonian.