An erection, especially in response to an attractive person.
When the blonde with the 36DD chest walked by his table, Bob was embarrassed he had given her the one-gun salute.
To commit suicide with the intent on making the "ultimate sacrifice" for a personal cause or a belief, disregarding the thoughts, opinions, and feelings of others entirely.
He ended his life with a "Fuck you!" attitude and a one-gun salute.