Gents fancy something vulgar .. (6,6)

I believe the answer is:

toilet humour

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'something vulgar' is the definition.
I don't know anything about this answer so I can't tell whether this works.

'gents fancy' is the wordplay.
'gents' becomes 'toilet' (men's toilet).
'fancy' becomes 'humour' (I can't justify this - if you can you should give a lot more credence to this answer).
'toilet'+'humour'='TOILET HUMOUR'

Can you help me to learn more?

I've seen this clue in The Irish Times.

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