When we're pouring someone some drink, we usually ask "say when". What's the typical answer to this phrase "say when".
As a joke we say "when" but in reality most people say "OK" or "that's enough"
Not a teacher -- AmE native
I say "when."
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.
It actually means something like 'Say (something appropriate) at the point at which I should stop pouring', so the logical/serious answer is, of course, "Stop!"/"Enough!" (etc.)
Humorously, however, many will intentionally misinterpret the instruction as 'Say (the word) "when"', and therefore simply reply "when".