Used to describe an erection so hard that, if given the chance, a dingo (Australia's native wild dog) would not be able to damage it.

Given the silliness of the statement, it's usually used to describe a non-sexual situation that a man would nonetheless enjoy very much, such as a sporting event.
When the Cats won the 2007 AFL Grand Final, for the next week I had a boner so hard a dingo couldn't have bitten through it. (boner, I've got a ... a dingo couldn't bite through - gotta use the original here)
by Choda Boy 57 May 7, 2008
Get the boner, I've got a ... a dingo couldn't bite through mug.