Doctors have documented numerous cases of insertion of foreign bodies into the urethra, typically as the result of auto-erotic activities. This can result in infections and serious internal bleeding.[1][2]
A wide variety of solid objects have been reported to have been inserted into the urethra, including batteries, safety pins, straws,[2] and telephone wires.[3] Liquefied objects have also been inserted into the urethra, such as an injection of cocaine[4] (which, arguably, had harmful results[5][clarification needed]).
The Chuck Palahniuk story "Guts", from the novel Haunted, includes the story of a boy in his early teens inserting candle wax into his urethra.[6]