whilst masturbating, one might make the common mistake of shoving a thin scrap of a candle in your dick hole. this causes great stimulation, however it may slip in and crystallize in your bladder. This is actually supposed to be done with a letter opener like the men who live in Arabia. Read the book "Haunted" by Chuck Palahniuk for more information. Look for the short story called "Guts" within the book.
Johnny made the common mistake of shoving urethra wax in his willy for stimulation. He eventually had to tell his parents that he was pissing blood because of the crystallized wax in his bladder. There goes the college fund.