Trust us occasionally to make disapproving noises (4)

I believe the answer is:

tuts

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'make disapproving noises' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'trust us occasionally' is the wordplay.
'occasionally' means one should take alternating letters (letters taken at regular intervals or occasions).
'trust'+'us'='trustus'
The alternating letters of 'trustus' are 'TUTS'.

'to' is the link.

Can you help me to learn more?

(Another definition for tuts that I've seen is " Makes disapproving sounds".)

I've seen this clue in The Irish Times.

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