Like the other definitions, a mild sweary word, but used as a get-out when you start to say "fuck" somewhere you can't. Often has a bit of a stutter at the start. Very similar to "sugar", in the sense Lucinda Green used it on television when a British horse missed a fence at the Olympic showjumping.
between his or her inner thighs with his or her hands. The goal of this action is to generate a loud noise. Fiddlesticking is a common practice among middle schoolers.
Joe: I am definitely better at fiddlesticking than you.
Ryan: No way bro, I can do it way faster and louder than you!