When you beat your pickle, often while watching loli hentai
"Dude there's a new episode of Boko No Pico want to come to my house so we can have a good time jerkin your gherkin?"
When someone really wants to eat a pickle. Even more so if it is of the Gherkin variety
Jerkin the gherkin is an uncommon term used to describe the action of masturbation.
Luni: Where did Radek go?
Gary: He is probably Jerkin the gherkin right now