Relax - on downers I'm finally calm, somehow (6,4)

I believe the answer is:

simmer down

'relax' is the definition.
(I've seen this in another clue)

'downers i'm finally calm somehow' is the wordplay.
'finally' indicates one should take the final letters.
'somehow' is an anagram indicator.
The last letter of 'calm' is 'm'.
'downers'+'im'+'m'='downersimm'
'downersimm' with letters rearranged gives 'SIMMER DOWN'.

'on' acts as a link.

I've seen this clue in The Irish Times.

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