Reading the post below reminds me of an interview I heard on the radio a few months back with Dave Dee (of Dave Dee, Dozy, Beaky, Mick and Tich fame), a group that had a few hit records in the nineteen sixties. Their "Legend of Xanadu" offering got to No. 1 in the UK and famously featured the sound of a bull-whip. Only it wasn't a bull-whip. What was it?

"...by zipping an empty beer bottle down the fretboard of a guitar while two small scraps of wood were slapped together."

Gosh - I'd all but forgotten I ever asked this question! Yes, you're right, and you qualify for a gold star. The group first tried using a real whip but the sound just didn't work. Hence the two bits of wood and the beer bottle. Fine song - and a fine answer!