lamb's tails

[Douglas G. Wilson]

>What constitutes lamb's tail shakes.  When folks say two shakes of a
>lamb's tail, they mean very quickly.  I have seen lambs shake their tails.
>  But I don't think I've ever seen just two shakes.  And, does a shift to
>the left and a shift to the right account for one shake or two?  I know
>that this is a frivolous question, however, it's been nagging me ever
>since my 13-year-old son asked me.

The lamb's tail is arbitrary, I believe. My OED shows "in the shake of a
hand" [meaning "in an instant" (apparently)] from 1816 (compare "in the
blink of an eye"), "in a couple of shakes" from 1840, "in two shakes" from
1883, etc.

N'archive at a glance shows "in two shakes of a sheep's tail" (1895), "...
lamb's tail" (1902), "... dog's tail" (1909), etc., as well as multiple
cases of "in two shakes" with no tail specified.

-- Doug Wilson