Toy sterilised after cutting down on aphrodisiac? (6)

I believe the answer is:

oyster

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

'aphrodisiac?' is the definition.
(I've seen this before)

'toy sterilised after cutting down' is the wordplay.
'OYSTER' is hidden in amongst the letters.
But, I'm uncertain how the hidden word is indicated.

'on' is the link.

Can you help me to learn more?

(Other definitions for oyster that I've seen before include "Bivalve - may be pearl carrier" , "Means to cross London" , "Shellfish (maybe the world!)" , "Type of mollusc" , "Pearl producer" .)

I've seen this clue in the Sydney Morning Herald.

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