Saying "when"

[vodkancoke]

Why when someone is, for example, pouring milk into tea for someone else, do they often say "Say when" ? Where does it come from?

Thank you :)

[Sipowicz]

Say when you want me to stop pouring.

[EcclesCake]

I've always assumed it is an abridged form of 'say when.....I should stop'.

[237SJ]

When to stop.

[vodkancoke]

Thank you all, I didn't think of it in that way! I'm such a dummy lol :)

[cupid04]

Have you had more vodka than coke today, lol!

[vodkancoke]

I wish that was the reason cupid! I'm just a bit of a bimbo clearly! lol :)

[Clanad]

The idiom is used quite early: Rudyard Kipling's A Conference of the Powers (1890):

"Following the first great law of the Army, which says ‘all property is common except money, and you’ve only got to ask the next man for that,’ The Infant offered tobacco and drink. It was the least he could do; but not the most lavish praise in the world held half as much appreciation and reverence as The Infant’s simple ‘Say when, sir,’ above the long glass.

Cleever said ‘when,’ and more thereto, for he was a golden talker, and he sat in the midst of hero-worship devoid of all taint of self-interest..."

[aelmpvw]

no one ever says 'say when' to me if there's alcohol involved

[AlwaysConfused]

I like a splash of milk in my tea. At work ( when everyone is aiming for the milk at the same time) someone asks 'semi-skimmed?' i say yes, and before i know it they are at my bloody cup with the milk . 'Say when', ooooh, I hate it. I end up with a teabag with my milk rather than milk with my tea!

[society]

lol @ "Have you had more vodka than coke today". Good one, Cupid.