Funny bone providing gentle stimulation (3-8)

I believe the answer is:

rib-tickling

'funny' is the definition.

'bone providing gentle stimulation' is the subsidiary indication.
'bone' becomes 'rib' (rib is a kind of bone).
'providing gentle stimulation' becomes 'tickling'.
'rib'+'tickling'='ribtickling'

I've seen this clue in The Times.

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