Crossword Genius

He yawns uncontrollably: should I stop? (3,4)

Ross

I believe the answer is:

say when

'should i stop?' is the definition.
(said when pouring a drink)

'he yawns uncontrollably' is the wordplay.
'uncontrollably' is an anagram indicator (I've seen this in other clues).
'he'+'yawns'='heyawns'
'heyawns' with letters rearranged gives 'SAY WHEN'.

(Other definitions for say when that I've seen before include "Tell me when to stop pouring" , "Words from the pourer?" , "Pourer's words" , "Request to be told to stop pouring drink" .)

I've seen this clue in The Guardian.
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