Circle jerk has two connoted meaning, similar in their senses.
One way of understanding circle jerk is quite literal; a group of men are standing in a circle, jerking off themselves together.
The other sense of the phrase is that a circle of men are talking about something with great agreement and shared ideas, jerking each other off with each other’s opinions.
Origin of the term
The term jerk off has been in use in relation to masturbating since the 1860’s and circle jerk was already heard in a song from the 1880’s about a Scottish orgy, “The Ball o’ Kirriemuir”.
Jim Croce did a recording of the song, with the questionable lines missing in 1973.
It was published in 1989.
Spread of the term
The expression was mentioned in the United Stated in 1958, in a book by Harrison Salisbury; The Shook-up Generation.
Here circle jerk is described as a common practice among the boys of the age.
In 1979 the punk band The Bedwetters renamed themselves Circle Jerk, becoming an iconic member of the hardcore scene.
During the AIDS crisis in the 80’s, the literal circle jerk started to take off among wary gays of the age to prevent the spread of HIV.
Its figurative use also became widely known, even used to describe the 2009 Academy Awards.
The term has been present on Urban Dictionary since 2003 at least.