A euphemism for the male sexual organ. Derived from the 1974 movie "2069: A Sex Odyssey", which is the first result on the internet movie database IMDB.com when a search is performed for "Gideon's Trumpet". As a euphemism, this phrase has no connection to the book of the same name by Anthony Lewis or the movie based on the book.
She enthusiastically blew Gideon's Trumpet.
by JoJoeJoh February 19, 2011