Top definition
When a penis becomes abnormally hard. This only occurs when a man is so turned on that he cannot think straight and becomes light headed. It is usually at the climax of an orgasm. It begins with light grunting but eventually leads to loud and sharp screams. An Idaho Diamond also has the potential to rip the skin of an anus when inserted beforehand. It is called an Idaho Diamond because the erection is as hard as a diamond.
Last night was amazing, Robert gave Tommy the Idaho Diamond of a lifetime.
by That's So Hard Like a Diamond January 09, 2011
Get the mug
Get a Idaho Diamond mug for your bunkmate Julia.