When people go to prison, they are not allowed to have things like colored pens, pencils or markers. They also cannot have tattoos made by anyone outside of the prison. But, some people want to have tattoos because it makes them feel good about themselves or because they want to show something that they believe in, like loyalty to a group.
Prison tattooing is when people get tattoos made inside prison by other inmates who have learned how to make tattoos using things like improvised needles made from things like pencil tips, guitar strings, or paper clips, and tattoo ink made from things like ashes, ink from pens, or melted plastic.
However, it is not safe to get prison tattoos because the needles used might carry dangerous diseases like HIV or Hepatitis C, and the ink used can be toxic to the skin. That is why it is really important for people to think carefully before getting a tattoo in prison and to wait until they are released and can go to a reputable tattoo artist with sterile needles and safe ink.