Telling tale, grin maniacally (8)

I believe the answer is:

relating

I'm a little stuck... Click here to teach me more about this clue!

'telling' is the definition.
(relating is a kind of telling)

'tale grin maniacally' is the wordplay.
'tale grin' can be anagrammed to 'RELATING'.
But, I'm not sure how the anagram is indicated.

Can you help me to learn more?

(Other definitions for relating that I've seen before include "Connecting things in thought or meaning" , "account" , "Rendering" , "Telling, narrating" , "Narrating, recounting" .)

I've seen this clue in The Times.

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