jerkin’ the gherkin

Definition

Slang

  • noun male masturbation. A rhyming witticism from around 1960, it replaced other rarer phrases employing the word jerk which had been in use since the mid-19th century, such as ‘jerk the turkey’, ‘jerk the jelly’, etc.
http://www.dictionarycentral.com/definition/jerkin-the-gherkin.html